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Grade 8 math worksheets

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Apply properties of integer exponents

Learning goals

  • Applies product, quotient, and power rules for integer exponents.
  • Uses zero and negative exponents correctly.
  • Rewrites equivalent exponential expressions.
  • Checks domain restrictions such as division by zero.

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Apply properties of integer exponents 1
Write \(4\cdot4\cdot4\) as a power. Name its base and exponent, and explain what the exponent counts.

Hints

- Identify the factor that keeps repeating. - Count how many copies of that factor are multiplied. - In a power, the large number and the small raised number have different roles.

Solution

1. The factor \(4\) appears three times, so the power is \(4^3\). 2. The base is \(4\), and the exponent is \(3\). The exponent counts the repeated factors.

Answer

\(4^3\). Base: \(4\). Exponent: \(3\) repeated factors.
Apply properties of integer exponents 2
Rewrite \(2^3\cdot2^2\) as one power of \(2\). Why can you add the exponents here?

Hints

- Expand each power as repeated multiplication if needed. - Count all the factors with the same base. - Think about which operation joins the two lists of factors.

Solution

1. The product is three factors of \(2\) followed by two more factors of \(2\). 2. There are five factors altogether, so \(2^3\cdot2^2=2^{3+2}=2^5\).

Answer

\(2^5\), because the product contains five factors of \(2\).
Apply properties of integer exponents 3
Simplify \(\frac{5^6}{5^4}\) by canceling matching factors. Write the answer as one power of \(5\).

Hints

- Write out repeated factors if the powers feel unfamiliar. - Each canceled pair has value one. - Count the uncanceled factors.

Solution

1. Expand numerator and denominator into six and four factors of \(5\), respectively. 2. Cancel four matching factors from top and bottom. 3. Two factors remain in the numerator, so the result is \(5^2\).

Answer

Cancel four matching factors of \(5\) in the numerator and denominator. Two factors remain above, so the answer is \(5^2\).
Apply properties of integer exponents 4
Complete the pattern: \(3^3=27\), \(3^2=9\), \(3^1=3\), \(3^0=\square\). What happens to the value each time the exponent goes down by one?

Hints

- Compare consecutive values in the pattern. - Identify the operation that takes \(27\) to \(9\), then \(9\) to \(3\). - Continue that same operation one more time.

Solution

1. Each step divides the previous value by \(3\). 2. After \(3^1=3\), divide by \(3\) again to get \(3^0=1\).

Answer

\(3^0=1\). Each step divides the value by \(3\).
Apply properties of integer exponents 5
Use the pattern \(2^1=2\), \(2^0=1\) to find \(2^{-1}\) and \(2^{-2}\). Explain how you continue the pattern.

Hints

- Compare the values of the two powers already given. - Keep the same operation when moving to a smaller exponent. - Do the values change sign as you continue the pattern? Check rather than guess from the exponent's sign.

Solution

1. When the exponent decreases by one, divide the value by the base \(2\). 2. Thus, \(2^{-1}=1\div2=\frac{1}{2}\). 3. Divide once more: \(2^{-2}=\frac{1}{2}\div2=\frac{1}{4}\).

Answer

\(2^{-1}=\frac{1}{2}\), \(2^{-2}=\frac{1}{4}\); each step divides by \(2\).
Apply properties of integer exponents 6
Which expression is negative: \((-3)^2\) or \(-3^2\)? Explain why parentheses change the result.

Hints

- Identify the base in each expression. - Write each expression as a multiplication before evaluating it. - If the minus sign is not part of the base, when is it applied?

Solution

1. In \((-3)^2\), the base is \(-3\), so \((-3)(-3)=9\). 2. In \(-3^2\), only \(3\) is squared, and the negative sign remains outside: \(-(3^2)=-9\). 3. Therefore \(-3^2\) is negative.

Answer

\(-3^2=-9\) is negative; \((-3)^2=9\) is positive. The parentheses make \(-3\) the base of the first power. Without them, only \(3\) is squared and the minus sign stays outside.
Apply properties of integer exponents 7
Simplify \(2x^2y \cdot 3x^3y\). a) \(6x^6y\) b) \(6x^6y^2\) c) \(6x^5y\) d) \(6x^5y^2\)

Hints

- Work with the coefficients and variables separately. - Add exponents when multiplying powers with the same base. - A variable with no written exponent has exponent \(1\).

Solution

1. Multiply the coefficients: \(2 \cdot 3 = 6\). 2. Add exponents for the same base: \(x^2 \cdot x^3 = x^{2+3} = x^5\). 3. Since each factor contains \(y^1\), \(y \cdot y = y^{1+1} = y^2\). 4. The product is \(6x^5y^2\).

Answer

d) \(6x^5y^2\)
Apply properties of integer exponents 8
Simplify each expression. a) \(\frac{(-3)^2}{-9}\) b) \(\frac{-3^2}{-9}\) c) \(-\frac{-3^2}{9}\)

Hints

- Determine whether the negative sign is included in the base being squared. - A quotient of two negative numbers is positive. - The product of two negative values is positive.

Solution

1. a) The parentheses make the negative part of the base: \((-3)^2 = 9\), so \(\frac{9}{-9} = -1\). 2. b) The exponent applies only to \(3\): \(-3^2 = -(3^2) = -9\), so \(\frac{-9}{-9} = 1\). 3. c) Inside the fraction, \(-3^2 = -9\). Therefore, \(-\frac{-9}{9} = -(-1) = 1\).

Answer

a) \(-1\) b) \(1\) c) \(1\)
Apply properties of integer exponents 9
Let \(x = -\frac{(-1)^{101}}{5}\). Is \(x\) to the left or right of \(0\) on a number line? Explain.

Hints

- First determine the sign of the power in the numerator. Does an odd or even exponent matter? - Consider what the negative sign in front of the fraction does. - Recall where positive and negative numbers lie relative to \(0\).

Solution

1. Since \(101\) is odd, \((-1)^{101} = -1\). 2. Substitute: \(x = -\frac{-1}{5} = \frac{1}{5}\). 3. Because \(\frac{1}{5} > 0\), the point is to the right of \(0\).

Answer

The value is to the right of \(0\) because \(x = \frac{1}{5}\), which is positive.
Apply properties of integer exponents 10
A pattern of products grows by adding one factor of \(-3\) in each row. Row 1: \((-3)\) Row 2: \((-3) \cdot (-3)\) Row 3: \((-3) \cdot (-3) \cdot (-3)\) a) Determine the sign of the product in Row 8 without calculating its value. Explain. b) Calculate the value of the product in Row 4.

Hints

- What sign results when two negative numbers are multiplied? - How does an even or odd number of negative factors affect the sign? - You can write each row as a power.

Solution

1. Row 8 contains eight negative factors. Because eight is even, the product is positive. 2. Row 4 is \((-3)^4\). Pairing the factors gives \(9 \cdot 9 = 81\).

Answer

a) Positive, because the product has an even number of negative factors. b) \(81\)
Apply properties of integer exponents 11
Evaluate each expression. For parts a)–d), first write the power as repeated multiplication. a) \((-3)^4\) b) \(-3^4\) c) \((-10)^3\) d) \(-10^3\) e) \((-1)^{100}\) Briefly explain why the notation in a) and b) has different meanings.

Hints

- Determine exactly what the exponent applies to. Is the negative sign inside parentheses? - Consider how multiplying an even or odd number of negative factors affects the sign. - Follow the order of operations when a negative sign is outside a power.

Solution

1. a) \((-3)^4 = (-3) \cdot (-3) \cdot (-3) \cdot (-3) = 81\). 2. b) \(-3^4 = -(3 \cdot 3 \cdot 3 \cdot 3) = -81\). 3. c) \((-10)^3 = (-10) \cdot (-10) \cdot (-10) = -1000\). 4. d) \(-10^3 = -(10 \cdot 10 \cdot 10) = -1000\). 5. e) Since \(100\) is even, \((-1)^{100} = 1\). 6. In a), the parentheses make \(-3\) the base. In b), the exponent applies only to \(3\), and the negative sign is applied afterward.

Answer

a) \(81\) b) \(-81\) c) \(-1000\) d) \(-1000\) e) \(1\) In a), the base is \(-3\). In b), the base is \(3\), and the negative sign is outside the power.
Apply properties of integer exponents 12
Order the quantities from least to greatest. (1) \(10^4\) (2) \(1000\) (3) \(10^2 \cdot 10^3\) (4) \(100{,}000\) (5) \(10^7 \div 10\)

Hints

- Rewrite each quantity as a power with base \(10\). - When multiplying or dividing powers with the same base, what happens to the exponents? - Count the zeros in \(100{,}000\).

Solution

1. Rewrite each quantity as a power of \(10\): (1) \(10^4\), (2) \(10^3\), (3) \(10^{2+3} = 10^5\), (4) \(10^5\), and (5) \(10^{7-1} = 10^6\). 2. Compare the exponents: \(3 < 4 < 5 < 6\). 3. Therefore, \(1000 < 10^4 < 10^2 \cdot 10^3 = 100{,}000 < 10^7 \div 10\).

Answer

\(1000 < 10^4 < 10^2 \cdot 10^3 = 100{,}000 < 10^7 \div 10\)
Apply properties of integer exponents 13
Insert \(<\), \(>\), or \(=\) in each blank. Briefly justify your choice using exponent properties. a) \((-1)^{10}\ \_\_\_\ (-1)^{11}\) b) \(-4^2\ \_\_\_\ (-4)^2\) c) \(3^{-2}\ \_\_\_\ (-3)^{-2}\)

Hints

- Check whether the exponent is even or odd. - Notice whether a negative sign is inside or outside parentheses. - A negative exponent creates a reciprocal; it does not make the value negative.

Solution

1. \((-1)^{10}=1\) because the exponent is even, while \((-1)^{11}=-1\). Therefore, \(1>-1\). 2. The expression \(-4^2\) means \(-(4^2)=-16\), while \((-4)^2=16\). Therefore, \(-16<16\). 3. \(3^{-2}=\frac{1}{9}\), and \((-3)^{-2}=\frac{1}{(-3)^2}=\frac{1}{9}\). Therefore, the expressions are equal.

Answer

a) \(>\) b) \(<\) c) \(=\)
Apply properties of integer exponents 14
Assume \(a\ne0\) and \(b\ne0\). Decide whether each statement is true or false. Correct each false statement. a) \(a^{-4}\cdot a^4=0\) b) \(\frac{b^2}{b^{-3}}=b^5\) c) \((2^{-1})^3=\frac{1}{8}\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract the denominator exponent when dividing. - Recall that a nonzero number to the zero power equals \(1\).

Solution

1. For a), \(a^{-4}a^4=a^0=1\), so the statement is false. 2. For b), \(\frac{b^2}{b^{-3}}=b^{2-(-3)}=b^5\), so the statement is true. 3. For c), \((2^{-1})^3=2^{-3}=\frac{1}{8}\), so the statement is true.

Answer

a) False. The correct equation is \(a^{-4}\cdot a^4=1\). b) True. c) True.
Apply properties of integer exponents 15
Simplify each expression and write the result as a single power of \(10\). a) \(\frac{1}{100000}\) b) \(0.001\cdot10^{-4}\) c) \(\frac{10^{-2}}{10^5}\) d) \((10^{-3})^2\cdot10^4\)

Hints

- Rewrite decimal powers of ten using exponents. - Add exponents when multiplying and subtract them when dividing. - Multiply exponents when raising a power to a power.

Solution

1. For a), \(100{,}000=10^5\), so \(\frac{1}{100000}=10^{-5}\). 2. For b), \(0.001=10^{-3}\), so \(10^{-3}\cdot10^{-4}=10^{-7}\). 3. For c), \(10^{-2}\div10^5=10^{-2-5}=10^{-7}\). 4. For d), \((10^{-3})^2\cdot10^4=10^{-6+4}=10^{-2}\).

Answer

a) \(10^{-5}\) b) \(10^{-7}\) c) \(10^{-7}\) d) \(10^{-2}\)
Apply properties of integer exponents 16
Assume all variables are nonzero. Simplify and write each result without negative exponents. a) \(a^5a^{-8}a^4\) b) \((-x)^2x^{-5}\) c) \(\frac{b^2}{b^{-3}}\)

Hints

- Add exponents when multiplying powers with the same base. - Square the negative base before combining powers. - Subtracting a negative exponent is addition.

Solution

1. For a), \(a^{5-8+4}=a\). 2. For b), \((-x)^2=x^2\), so \(x^2x^{-5}=x^{-3}=\frac{1}{x^3}\). 3. For c), \(b^{2-(-3)}=b^5\).

Answer

a) \(a\) b) \(\frac{1}{x^3}\) c) \(b^5\)
Apply properties of integer exponents 17
Determine whether each statement is true. Correct every false statement. a) \((5z)^2 = 25z^2\) b) \((-x)^2 = -x^2\) c) \(a^4 \cdot a^2 = a^8\) d) \((2k)^3 = 8k^3\)

Hints

- An exponent outside parentheses applies to every factor inside. - Add exponents when multiplying powers with the same base. - Distinguish a negative sign inside the base from one outside a power.

Solution

1. a) True: \((5z)^2 = 5^2z^2 = 25z^2\). 2. b) False: \((-x)^2 = (-x)(-x) = x^2\). 3. c) False: powers with the same base are multiplied by adding exponents, so \(a^4 \cdot a^2 = a^6\). 4. d) True: \((2k)^3 = 2^3k^3 = 8k^3\).

Answer

a) True b) False; \((-x)^2 = x^2\) c) False; \(a^4 \cdot a^2 = a^6\) d) True
Apply properties of integer exponents 18
Three of these expressions are equivalent for \(x\ne0\), and one is not. Identify the expression that is not equivalent and justify your choice. A. \(\frac{4}{x^2}\) B. \(4x^{-2}\) C. \((2x)^{-2}\cdot16\) D. \(4\cdot\frac{1}{x^{-2}}\)

Hints

- Rewrite every negative exponent as a reciprocal. - Apply the exponent to the coefficient inside parentheses. - Put all four expressions in the same form before comparing.

Solution

1. \(A=\frac{4}{x^2}\). 2. \(B=4x^{-2}=\frac{4}{x^2}\). 3. \(C=(2x)^{-2}\cdot16=\frac{16}{(2x)^2}=\frac{4}{x^2}\). 4. \(D=4\cdot\frac{1}{x^{-2}}=4x^2\), so it is not equivalent to the others for all nonzero \(x\).

Answer

D is not equivalent. A, B, and C simplify to \(\frac{4}{x^2}\), while D simplifies to \(4x^2\).
Apply properties of integer exponents 19
Consider the expressions I. \(10^{-2}\), II. \((-10)^{-2}\), and III. \(-10^{-2}\). a) Find the exact decimal value of each expression. b) Order the expressions from least to greatest using \(<\) or \(=\).

Hints

- Identify whether the negative sign is part of the base. - Rewrite each negative exponent as a reciprocal. - Compare the resulting decimal values.

Solution

1. \(10^{-2}=\frac{1}{100}=0.01\). 2. \((-10)^{-2}=\frac{1}{(-10)^2}=0.01\). 3. \(-10^{-2}=-\frac{1}{100}=-0.01\). 4. Therefore, \(-0.01<0.01=0.01\), so III \(<\) I \(=\) II.

Answer

a) I: \(0.01\); II: \(0.01\); III: \(-0.01\) b) III \(<\) I \(=\) II
Apply properties of integer exponents 20
Simplify each expression. a) \(5a^3 \cdot 3a^2\) b) \(18b^6 \div (3b^2 \cdot 2b)\), where \(b \ne 0\)

Hints

- Work with coefficients and powers separately when multiplying. - In part b), simplify the expression in parentheses first.

Solution

1. a) Multiply the coefficients and add the exponents: \(5 \cdot 3 = 15\) and \(a^3 \cdot a^2 = a^5\). The result is \(15a^5\). 2. b) First simplify the divisor: \(3b^2 \cdot 2b = 6b^3\). Then \(18b^6 \div 6b^3 = 3b^{6-3} = 3b^3\).

Answer

a) \(15a^5\) b) \(3b^3\)
Apply properties of integer exponents 21
Assume \(y\ne0\). Simplify using exponent properties: \(y^{-5}(y^2)^3\)

Hints

- Multiply exponents when raising a power to a power. - Add exponents when multiplying powers with the same base.

Solution

1. Raise the power to a power: \((y^2)^3=y^6\). 2. Multiply powers with the same base: \(y^{-5}y^6=y^{-5+6}=y\).

Answer

\(y\)
Apply properties of integer exponents 22
Evaluate without a calculator. Use exponent properties to simplify. a) \(3^6\cdot3^{-7}\cdot9\) b) \(10^{-2}\div10^{-5}\cdot0.1^2\)

Hints

- Rewrite \(9\) and \(0.1\) as powers with matching bases. - Add exponents when multiplying and subtract when dividing. - Follow multiplication and division from left to right.

Solution

1. For a), write \(9=3^2\): \(3^{6-7+2}=3\). 2. For b), \(10^{-2}\div10^{-5}=10^3\), and \(0.1^2=(10^{-1})^2=10^{-2}\). 3. Therefore, \(10^3\cdot10^{-2}=10\).

Answer

a) \(3\) b) \(10\)
Apply properties of integer exponents 23
Use exponent properties to simplify. Write answers without negative exponents. Assume \(x\ne0\) in part a and \(a\ne0\), \(b\ne0\) in part b. a) \(\frac{x^8\cdot x^{-5}}{x^2}\) b) \(\frac{(a^3b^{-2})^2}{a^4b^{-4}}\)

Hints

- Combine like bases by adding or subtracting exponents. - Apply the outside exponent before simplifying a quotient.

Solution

1. \(\frac{x^8\cdot x^{-5}}{x^2}=x^{8-5-2}=x\). 2. The numerator is \(a^6b^{-4}\). Dividing by \(a^4b^{-4}\) gives \(a^2\).

Answer

a) \(x\) b) \(a^2\)
Apply properties of integer exponents 24
Rewrite each product using exponents. 1) \(8 \cdot 8 \cdot 8 \cdot 8 \cdot 8 \cdot 8\) 2) \(z \cdot z \cdot z \cdot z\) 3) \(3 \cdot 3 \cdot 3 \cdot a \cdot a \cdot b \cdot b \cdot b \cdot b\) 4) Which expression can be written as \(x^4\): \(x + x + x + x\) or \(x \cdot x \cdot x \cdot x\)? Briefly explain.

Hints

- An exponent tells how many times the base is used as a factor. - Distinguish repeated addition from repeated multiplication. - Group equal factors before writing powers.

Solution

1. Six equal factors of \(8\) give \(8^6\). 2. Four equal factors of \(z\) give \(z^4\). 3. Group equal factors: \(3^3a^2b^4\). 4. \(x^4\) represents repeated multiplication, so \(x \cdot x \cdot x \cdot x = x^4\). The sum \(x + x + x + x\) equals \(4x\).

Answer

1) \(8^6\) 2) \(z^4\) 3) \(3^3a^2b^4\) 4) \(x \cdot x \cdot x \cdot x\), because exponents represent repeated multiplication.
Apply properties of integer exponents 25
Rewrite each expression as concisely as possible using exponents. 1) A product of nine factors of \(c\) 2) \(4 \cdot 4 \cdot r \cdot r \cdot r + s \cdot s \cdot s \cdot s \cdot s\) 3) \(x \cdot x \cdot y \cdot y \cdot y \cdot x \cdot y\) 4) The product \(p \cdot p \cdot \ldots \cdot p\) contains \(n\) factors. Write it using exponent notation.

Hints

- Rearrange factors so equal variables are next to each other. - A plus sign separates terms; do not combine factors across it. - Use the definition of a power with \(n\) equal factors.

Solution

1. Nine factors of \(c\) give \(c^9\). 2. Group equal factors in each term: \(4^2r^3 + s^5\). 3. There are three factors of \(x\) and four factors of \(y\), so the product is \(x^3y^4\). 4. A product of \(n\) factors of \(p\) is \(p^n\).

Answer

1) \(c^9\) 2) \(4^2r^3 + s^5\) 3) \(x^3y^4\) 4) \(p^n\)
Apply properties of integer exponents 26
Convert each expression to the other form. Expand powers as products, and rewrite products using exponents. 1) \(6^3\) 2) \(b \cdot b \cdot b \cdot b\) 3) \(3 \cdot x \cdot x \cdot y \cdot y \cdot y\) 4) \((a + b)^2\) 5) \(7 \cdot m \cdot m\)

Hints

- An exponent tells how many equal factors are multiplied. - Identify the complete base of each power. - Keep coefficients separate from exponents on variables.

Solution

1. \(6^3 = 6 \cdot 6 \cdot 6\). 2. Four factors of \(b\) give \(b^4\). 3. Two factors of \(x\) and three factors of \(y\) give \(3x^2y^3\). 4. The entire binomial is the base: \((a + b)^2 = (a + b)(a + b)\). 5. Two factors of \(m\) give \(7m^2\).

Answer

1) \(6 \cdot 6 \cdot 6\) 2) \(b^4\) 3) \(3x^2y^3\) 4) \((a + b)(a + b)\) 5) \(7m^2\)
Apply properties of integer exponents 27
Write each expression as concisely as possible. Use coefficients for repeated addition and exponents for repeated multiplication. 1) \(x \cdot x \cdot x + x \cdot x \cdot x\) 2) \(a \cdot a \cdot b \cdot b \cdot b + a \cdot a \cdot b \cdot b \cdot b + a \cdot a \cdot b \cdot b \cdot b\) 3) \((m + n)(m + n) + (m + n)(m + n) + (m + n)(m + n) + (m + n)(m + n)\)

Hints

- First rewrite one repeated product using exponents. - Then count how many times that identical term is added. - Keep an entire binomial together when it is the repeated factor.

Solution

1. Each repeated product is \(x^3\), and it appears twice, so the expression is \(2x^3\). 2. Each repeated product is \(a^2b^3\), and it appears three times, so the expression is \(3a^2b^3\). 3. Each repeated product is \((m + n)^2\), and it appears four times, so the expression is \(4(m + n)^2\).

Answer

1) \(2x^3\) 2) \(3a^2b^3\) 3) \(4(m + n)^2\)
Apply properties of integer exponents 28
Evaluate each expression. Pay close attention to parentheses and negative signs. 1) \(-4^2\) 2) \((-4)^2\) 3) \((-1)^{50}\) 4) \(\left(-\frac{1}{2}\right)^4\) 5) \(-(-2)^3\)

Hints

- Determine whether the negative sign is part of the base. - Compare \(-a^n\) with \((-a)^n\). - Evaluate a power before applying a negative sign outside it.

Solution

1. \(-4^2 = -(4^2) = -16\). 2. \((-4)^2 = 16\). 3. Since \(50\) is even, \((-1)^{50} = 1\). 4. \(\left(-\frac{1}{2}\right)^4 = \frac{1}{16}\). 5. First, \((-2)^3 = -8\). Then \(-(-8) = 8\).

Answer

1) \(-16\) 2) \(16\) 3) \(1\) 4) \(\frac{1}{16}\) 5) \(8\)
Apply properties of integer exponents 29
Simplify each product. a) \(x^4 \cdot x^5\) b) \((-a^3) \cdot a^2\) c) \(y \cdot y^4 \cdot y^2\) d) \((-m^2)(-m^6)\) e) \(b^n \cdot b^3\)

Hints

- Add exponents when multiplying powers with the same base. - A variable without a written exponent has exponent \(1\). - Apply the sign rules separately from the exponent rule.

Solution

1. Add exponents when multiplying powers with the same base. 2. a) \(x^{4+5} = x^9\). 3. b) \(-a^{3+2} = -a^5\). 4. c) \(y^{1+4+2} = y^7\). 5. d) The negative signs multiply to a positive sign, giving \(m^{2+6} = m^8\). 6. e) \(b^{n+3}\).

Answer

a) \(x^9\) b) \(-a^5\) c) \(y^7\) d) \(m^8\) e) \(b^{n+3}\)
Apply properties of integer exponents 30
Simplify each product. a) \(6x^2 \cdot 4x^5\) b) \((-3a^4)(8a^3)\) c) \(0.4y \cdot (-5y^4)\) d) \((-7b^2)(-2b^2)\) e) \(\frac{2}{5}z^6 \cdot 10z^2\)

Hints

- Multiply the coefficients separately. - Add exponents when multiplying powers with the same base. - Apply the sign rules for multiplication.

Solution

1. a) \((6 \cdot 4)x^{2+5} = 24x^7\). 2. b) \((-3 \cdot 8)a^{4+3} = -24a^7\). 3. c) \((0.4 \cdot -5)y^{1+4} = -2y^5\). 4. d) \((-7 \cdot -2)b^{2+2} = 14b^4\). 5. e) \(\left(\frac{2}{5} \cdot 10\right)z^{6+2} = 4z^8\).

Answer

a) \(24x^7\) b) \(-24a^7\) c) \(-2y^5\) d) \(14b^4\) e) \(4z^8\)
Apply properties of integer exponents 31
Multiply and simplify each pair of monomials. 1) \((-5a^3b)(4a^2b^4)\) 2) \((0.8x^2y^3)(-0.5xy)\) 3) \((-6m^4n^2)(-3m^2n^5)\)

Hints

- Multiply the coefficients separately. - Add exponents for each common variable base. - Apply the sign rules for multiplication.

Solution

1. \((-5 \cdot 4)a^{3+2}b^{1+4} = -20a^5b^5\). 2. \((0.8 \cdot -0.5)x^{2+1}y^{3+1} = -0.4x^3y^4\). 3. \((-6 \cdot -3)m^{4+2}n^{2+5} = 18m^6n^7\).

Answer

1) \(-20a^5b^5\) 2) \(-0.4x^3y^4\) 3) \(18m^6n^7\)
Apply properties of integer exponents 32
Simplify each expression. 1) \((4a^5)^2\) 2) \((-3b^2)^3\) 3) \(\left(\frac{1}{2}x^3\right)^4\) 4) \((-y^4)^2\)

Hints

- Raise every factor inside the parentheses to the outside power. - Multiply exponents when raising a power to a power. - Use even and odd exponents to determine the sign.

Solution

1. \((4a^5)^2 = 4^2a^{5 \cdot 2} = 16a^{10}\). 2. \((-3b^2)^3 = (-3)^3b^{2 \cdot 3} = -27b^6\). 3. \(\left(\frac{1}{2}x^3\right)^4 = \frac{1}{16}x^{12}\). 4. \((-y^4)^2 = (-1)^2y^{4 \cdot 2} = y^8\).

Answer

1) \(16a^{10}\) 2) \(-27b^6\) 3) \(\frac{1}{16}x^{12}\) 4) \(y^8\)
Apply properties of integer exponents 33
Simplify each expression as one power of \(10\). a) \(10^4 \cdot 10^3\) b) \(\frac{10^7}{10^2}\) c) \(10^2 \cdot 10^2 \cdot 10^2\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract exponents when dividing powers with the same base.

Solution

1. a) Add exponents: \(10^{4+3} = 10^7\). 2. b) Subtract exponents: \(10^{7-2} = 10^5\). 3. c) Add all exponents: \(10^{2+2+2} = 10^6\).

Answer

a) \(10^7\) b) \(10^5\) c) \(10^6\)
Apply properties of integer exponents 34
Evaluate each expression in two ways: first by evaluating inside the parentheses, and then by using a property of exponents. a) \((4 \cdot 5)^3\) b) \((2^3)^2\)

Hints

- What do you get when you evaluate the expression inside the parentheses first? - Which property simplifies a power raised to another power? - How can a power of a product be applied to each factor?

Solution

1. For a), evaluate inside the parentheses first: \(4 \cdot 5 = 20\), so \(20^3 = 8000\). 2. Using the power of a product property: \((4 \cdot 5)^3 = 4^3 \cdot 5^3 = 64 \cdot 125 = 8000\). 3. For b), evaluate the inner power first: \(2^3 = 8\), so \(8^2 = 64\). 4. Using the power of a power property: \((2^3)^2 = 2^{3 \cdot 2} = 2^6 = 64\).

Answer

a) \(8000\) b) \(64\)
Apply properties of integer exponents 35
Let \(A = [(-2)^2]^3\) and \(B = [(-2)^3]^2\). a) Evaluate \(A\) and \(B\) step by step, working from the inside out. b) Use a property of exponents to write both expressions as the same power with base \(-2\). Explain why this shows that the expressions are equal.

Hints

- Pay attention to whether the exponent on a negative base is even or odd. - Which property applies to a power raised to another power? - Does changing the order of the two exponent factors change their product?

Solution

1. Evaluate \(A\): \((-2)^2 = 4\), and then \(4^3 = 64\). 2. Evaluate \(B\): \((-2)^3 = -8\), and then \((-8)^2 = 64\). 3. Apply the power of a power property, \((a^m)^n = a^{mn}\). 4. \(A = (-2)^{2 \cdot 3} = (-2)^6\). 5. \(B = (-2)^{3 \cdot 2} = (-2)^6\). 6. Both expressions simplify to the same power, so they are equal.

Answer

a) \(A = 64\); \(B = 64\) b) \(A = (-2)^{2 \cdot 3} = (-2)^6\) and \(B = (-2)^{3 \cdot 2} = (-2)^6\). Therefore, \(A = B\).
Apply properties of integer exponents 36
Evaluate using exponent properties. 1) \(2^4\cdot2^{-2}\) 2) \(\left(\frac{1}{3}\right)^{-3}\cdot3^{-2}\) 3) \(10^{-2}\cdot0.1^{-3}\)

Hints

- A reciprocal base reverses the sign of an exponent. - Add exponents when multiplying like bases. - Rewrite \(0.1\) as a power of \(10\).

Solution

1. \(2^4\cdot2^{-2}=2^{4-2}=2^2=4\). 2. \(\left(\frac{1}{3}\right)^{-3}=3^3\), so \(3^3\cdot3^{-2}=3\). 3. Since \(0.1=10^{-1}\), \(10^{-2}\cdot0.1^{-3}=10^{-2}\cdot(10^{-1})^{-3}=10^{-2}\cdot10^3=10\).

Answer

1) \(4\) 2) \(3\) 3) \(10\)
Apply properties of integer exponents 37
Evaluate each expression. Follow the order of operations. 1) \(\left[6-2\cdot\left(\frac{17}{5}\right)^0\right]^{-2}\) 2) \(\frac{5^{-1}\cdot25^2}{0.2^{-2}}\)

Hints

- A nonzero base raised to the zero power equals \(1\). - Follow parentheses, exponents, multiplication and division, then addition and subtraction. - Rewrite all quantities with base \(5\) when possible.

Solution

1. Since \(\left(\frac{17}{5}\right)^0=1\), the bracket equals \(6-2=4\). Thus \(4^{-2}=\frac{1}{16}=0.0625\). 2. Write all factors with base \(5\): \(25^2=5^4\) and \(0.2^{-2}=\left(\frac{1}{5}\right)^{-2}=5^2\). Therefore, \(\frac{5^{-1}\cdot5^4}{5^2}=5\).

Answer

1) \(\frac{1}{16}\), or \(0.0625\) 2) \(5\)
Apply properties of integer exponents 38
Rewrite each expression without a fraction bar by using negative exponents. a) \(\frac{1}{10000}\) b) \(\frac{1}{32}\) c) \(\frac{4}{x^3}\), where \(x\ne0\) d) \(\frac{y^5}{z^2}\), where \(z\ne0\)

Hints

- A factor moved from the denominator to the numerator receives a negative exponent. - Rewrite numerical denominators as powers. - Keep coefficients and numerator factors unchanged.

Solution

1. Since \(10{,}000=10^4\), \(\frac{1}{10000}=10^{-4}\). 2. Since \(32=2^5\), \(\frac{1}{32}=2^{-5}\). 3. \(\frac{4}{x^3}=4x^{-3}\). 4. \(\frac{y^5}{z^2}=y^5z^{-2}\).

Answer

a) \(10^{-4}\) b) \(2^{-5}\) c) \(4x^{-3}\) d) \(y^5z^{-2}\)
Apply properties of integer exponents 39
Rewrite each rational expression without a fraction bar by using negative exponents. 1) \(\frac{12}{x^5}\), where \(x\ne0\) 2) \(\frac{1}{(a+b)^3}\), where \(a+b\ne0\) 3) \(\frac{1}{m^2}+\frac{1}{n^2}\), where \(m\ne0\) and \(n\ne0\) 4) \(\frac{x-y}{z^2}\), where \(z\ne0\)

Hints

- Treat a parenthetical expression as a single base. - Change the sign of an exponent when moving a factor across the fraction bar. - Use parentheses around a numerator with more than one term.

Solution

1. \(\frac{12}{x^5}=12x^{-5}\). 2. \(\frac{1}{(a+b)^3}=(a+b)^{-3}\). 3. \(\frac{1}{m^2}+\frac{1}{n^2}=m^{-2}+n^{-2}\). 4. \(\frac{x-y}{z^2}=(x-y)z^{-2}\).

Answer

1) \(12x^{-5}\) 2) \((a+b)^{-3}\) 3) \(m^{-2}+n^{-2}\) 4) \((x-y)z^{-2}\)
Apply properties of integer exponents 40
Let \(T=\frac{5a^{-n}b^2}{2c^{-3}d}\), where \(a,b,c,d\ne0\) and \(n\) is a natural number. 1. Rewrite the expression with no fraction bar, using negative exponents as needed. 2. Rewrite the expression with no negative exponents.

Hints

- Change an exponent’s sign when moving a factor across the fraction bar. - Convert \(\frac{5}{2}\) to a decimal for part 1. - In part 2, move all negative powers to the opposite side of the fraction bar.

Solution

1. Move the denominator factors to the numerator: \(T=2.5a^{-n}b^2c^3d^{-1}\). 2. Move factors with negative exponents to the denominator: \(T=\frac{5b^2c^3}{2a^nd}\).

Answer

1) \(2.5a^{-n}b^2c^3d^{-1}\) 2) \(\frac{5b^2c^3}{2a^nd}\)
Apply properties of integer exponents 41
Rewrite each rational expression with no fraction bar by using negative exponents. 1) \(\frac{12}{a^5}\), where \(a\ne0\) 2) \(\frac{3x^2}{4y^3}\), where \(y\ne0\) 3) \(\frac{2}{3(m+n)^4}\), where \(m+n\ne0\) 4) \(\frac{ab}{c}\), where \(c\ne0\)

Hints

- Treat every denominator factor as a factor with a negative exponent. - Constant denominators can also be written using negative exponents. - Keep parentheses around a multi-term base.

Solution

1. \(\frac{12}{a^5}=12a^{-5}\). 2. \(\frac{3x^2}{4y^3}=3\cdot4^{-1}x^2y^{-3}\). 3. \(\frac{2}{3(m+n)^4}=2\cdot3^{-1}(m+n)^{-4}\). 4. \(\frac{ab}{c}=abc^{-1}\).

Answer

1) \(12a^{-5}\) 2) \(3\cdot4^{-1}x^2y^{-3}\) 3) \(2\cdot3^{-1}(m+n)^{-4}\) 4) \(abc^{-1}\)
Apply properties of integer exponents 42
For \(x\ne0\) and \(y\ne0\), simplify \(A=\frac{x^{-1}y^{-1}}{(xy)^{-2}}\). Then evaluate the result for \(x=2\) and \(y=3\).

Hints

- Apply the exponent to both factors in \(xy\). - Subtract the denominator exponent for each variable. - Substitute only after simplifying the expression.

Solution

1. Rewrite the denominator: \((xy)^{-2}=x^{-2}y^{-2}\). 2. Divide powers with the same bases: \(A=x^{-1-(-2)}y^{-1-(-2)}=xy\). 3. For \(x=2\) and \(y=3\), \(A=2\cdot3=6\).

Answer

The simplified expression is \(xy\). For \(x=2\) and \(y=3\), the value is \(6\).
Apply properties of integer exponents 43
For positive integer \(n\) and nonzero \(a\) and \(b\), rewrite \(T=a^{-n}b^n\) without negative exponents. Then evaluate the result for \(a=2\), \(b=6\), and \(n=2\).

Hints

- Rewrite \(a^{-n}\) as a reciprocal. - Combine the two factors into one quotient. - Substitute only after the expression has no negative exponents.

Solution

1. Rewrite the negative power as a reciprocal: \(a^{-n}=\frac{1}{a^n}\). 2. Therefore, \(T=\frac{b^n}{a^n}=\left(\frac{b}{a}\right)^n\). 3. For \(a=2\), \(b=6\), and \(n=2\), \(T=\left(\frac62\right)^2=3^2=9\).

Answer

\(T=\frac{b^n}{a^n}=\left(\frac{b}{a}\right)^n\). The numerical value is \(9\).
Apply properties of integer exponents 44
Complete the pattern by dividing by \(5\) each time the exponent decreases by \(1\). Then write the last three powers without negative exponents. <table><tr><th>Exponent</th><td>\(3\)</td><td>\(2\)</td><td>\(1\)</td><td>\(0\)</td><td>\(-1\)</td><td>\(-2\)</td></tr><tr><th>Value</th><td>\(125\)</td><td>\(25\)</td><td>\(5\)</td><td>?</td><td>?</td><td>?</td></tr></table>

Hints

- Compare each value with the one immediately to its left. - Decreasing an exponent by \(1\) divides the value by the base. - Continue the same pattern through exponent \(0\) and into the negative exponents.

Solution

1. Each time the exponent decreases by \(1\), divide the preceding value by \(5\). 2. \(5\div5=1\), so \(5^0=1\). 3. \(1\div5=\frac{1}{5}\), so \(5^{-1}=\frac{1}{5}\). 4. \(\frac{1}{5}\div5=\frac{1}{25}\), so \(5^{-2}=\frac{1}{25}\).

Answer

The missing values are \(1\), \(\frac{1}{5}\), and \(\frac{1}{25}\). Thus, \(5^0=1\), \(5^{-1}=\frac{1}{5}\), and \(5^{-2}=\frac{1}{25}\).
Apply properties of integer exponents 45
Which is equal to \((2^3)^2\): \(2^5\) or \(2^6\)? Show why by writing the outside square as a product of two copies of \(2^3\).

Hints

- What multiplication does the outside square ask you to do? - Expand only far enough to count the equal-base factors. - Compare the exponent you counted with each offered choice.

Solution

1. The square means \((2^3)^2=2^3\cdot2^3\). 2. Each copy has three factors of \(2\), giving six altogether. 3. Therefore \((2^3)^2=2^{3\cdot2}=2^6\), not \(2^5\).

Answer

\(2^6\), because the two copies contain six factors of \(2\).
Apply properties of integer exponents 46
Each time a sheet of paper is folded in half, the number of layers doubles. After \(n\) folds there are \(2^n\) layers. How many folds produce \(32\) layers? Explain using a power of \(2\).

Hints

- What is the exponent in the formula when there have been no folds? - Make a short list of layer counts for the first few folds. - Which exponent gives the number of layers in the question?

Solution

1. The number of layers must satisfy \(2^n=32\). 2. Since \(2^5=32\), \(n=5\).

Answer

\(5\) folds, because \(2^5=32\).
Apply properties of integer exponents 47
Order the values from least to greatest. \(A = \frac{(-1)^3}{2}\) \(B = \frac{-1^4}{-4}\) \(C = -\frac{(-1)^2}{8}\)

Hints

- Evaluate each expression separately. - In \(B\), determine whether the exponent applies to the negative sign. - Compare the resulting rational numbers on a number line or by using common denominators.

Solution

1. Evaluate \(A\): \((-1)^3 = -1\), so \(A = -\frac{1}{2}\). 2. Evaluate \(B\): the exponent applies before the leading negative sign, so \(-1^4 = -(1^4) = -1\). Thus, \(B = \frac{-1}{-4} = \frac{1}{4}\). 3. Evaluate \(C\): \((-1)^2 = 1\), so \(C = -\frac{1}{8}\). 4. Compare the values: \(-\frac{1}{2} < -\frac{1}{8} < \frac{1}{4}\). Therefore, \(A < C < B\).

Answer

\(A < C < B\)
Apply properties of integer exponents 48
Consider these expressions. Expression A: \((-10)^3\) Expression B: \((-1)^4 \cdot 10^4\) Expression C: \((-10) \cdot (-10) \cdot (-10) \cdot (-10) \cdot (-10)\) a) Which expression has the least value? Explain. b) Which expressions have positive values? c) What is the absolute value of Expression B?

Hints

- Recall how an even or odd exponent affects the sign of a power with a negative base. - On a number line, a negative number with greater absolute value is farther left. - Absolute value is distance from \(0\).

Solution

1. Expression A is \((-10)^3 = -1000\). 2. Expression B is \((-1)^4 \cdot 10^4 = 1 \cdot 10^4 = 10{,}000\). 3. Expression C is \((-10)^5 = -100{,}000\). 4. Since \(-100{,}000 < -1000 < 10{,}000\), Expression C has the least value. 5. Only Expression B is positive. 6. The absolute value of Expression B is \(|10{,}000| = 10{,}000\).

Answer

a) Expression C, with a value of \(-100{,}000\) b) Expression B only c) \(10{,}000\)
Apply properties of integer exponents 49
Consider the sequence \((-2)^1, (-2)^2, (-2)^3, (-2)^4, \ldots\). a) Calculate the first five terms. b) Determine the sign of Term 15 and Term 20 without calculating their exact values. Explain. c) What is the sign of \(-(-2)^4\)? Evaluate the expression step by step.

Hints

- Look for a pattern in the signs of consecutive terms. - Recall how even and odd exponents affect a negative base. - In part c), evaluate the power before applying the outside negative sign.

Solution

1. The first five terms are \((-2)^1 = -2\), \((-2)^2 = 4\), \((-2)^3 = -8\), \((-2)^4 = 16\), and \((-2)^5 = -32\). 2. Term 15 is \((-2)^{15}\). Since \(15\) is odd, the term is negative. Term 20 is \((-2)^{20}\). Since \(20\) is even, the term is positive. 3. First evaluate the power: \((-2)^4 = 16\). Then apply the outside negative sign: \(-16\). The expression is negative.

Answer

a) \(-2, 4, -8, 16, -32\) b) Term 15 is negative, and Term 20 is positive. c) Negative; \(-(-2)^4 = -16\)
Apply properties of integer exponents 50
Compare the expressions \(x^2\) and \(x^3\). a) Calculate both values when \(x = -3\). b) For any negative value of \(x\), which expression is always greater: \(x^2\) or \(x^3\)? Explain using signs. c) Does your conclusion from part b) hold for every positive value of \(x\)? Test \(x = 0.5\) and \(x = 2\).

Hints

- Every positive number is greater than every negative number. - Test both a positive number between \(0\) and \(1\) and a positive number greater than \(1\). - Consider what happens when a positive value is multiplied by a number between \(0\) and \(1\).

Solution

1. For \(x = -3\), \(x^2 = (-3)^2 = 9\) and \(x^3 = (-3)^3 = -27\). 2. For any negative \(x\), \(x^2\) is positive and \(x^3\) is negative. Therefore, \(x^2 > x^3\). 3. For \(x = 0.5\), \(x^2 = 0.25\) and \(x^3 = 0.125\), so \(x^2 > x^3\). 4. For \(x = 2\), \(x^2 = 4\) and \(x^3 = 8\), so \(x^3 > x^2\). Therefore, the conclusion does not hold for every positive \(x\).

Answer

a) \(x^2 = 9\) and \(x^3 = -27\) b) \(x^2\), because it is positive while \(x^3\) is negative for every negative \(x\) c) No. For \(x = 0.5\), \(0.25 > 0.125\), but for \(x = 2\), \(8 > 4\).
Apply properties of integer exponents 51
Let \(A = x^3 \cdot x^2\), \(B = (x^2)^4\), \(C = x^9 \div x^2\), and \(D = x^5 + x^5\). Simplify each expression. Assume \(x \ne 0\) for Expression C. Which expression has the greatest value when \(x = 10\)?

Hints

- Apply the properties for multiplying, dividing, and raising powers to powers. - In Expression D, distinguish addition from multiplication. - After substitution, compare the powers of \(10\).

Solution

1. Apply the exponent properties: \(A = x^5\), \(B = x^8\), \(C = x^7\), and \(D = 2x^5\). 2. At \(x = 10\), the values are \(A = 10^5 = 100{,}000\), \(B = 10^8 = 100{,}000{,}000\), \(C = 10^7 = 10{,}000{,}000\), and \(D = 2 \cdot 10^5 = 200{,}000\). 3. Expression B has the greatest value.

Answer

\(A = x^5\) \(B = x^8\) \(C = x^7\) \(D = 2x^5\) When \(x = 10\), Expression B has the greatest value, \(100{,}000{,}000\).
Apply properties of integer exponents 52
Rewrite each expression as a power with base \(2\). Then identify the expression with the least value and the expression with the greatest value. (1) \(16^3\) (2) \(4^7\) (3) \(2^{11}\) (4) \(8^4\) (5) \(32^2\)

Hints

- Write \(4\), \(8\), \(16\), and \(32\) as powers of \(2\). - Use \((a^m)^n = a^{mn}\). - Once the bases match, compare the exponents.

Solution

1. Rewrite each base as a power of \(2\): (1) \((2^4)^3 = 2^{12}\), (2) \((2^2)^7 = 2^{14}\), (3) \(2^{11}\), (4) \((2^3)^4 = 2^{12}\), and (5) \((2^5)^2 = 2^{10}\). 2. Compare the exponents: \(10 < 11 < 12 < 14\). 3. Therefore, \(32^2\) has the least value, and \(4^7\) has the greatest value.

Answer

(1) \(2^{12}\) (2) \(2^{14}\) (3) \(2^{11}\) (4) \(2^{12}\) (5) \(2^{10}\) Least: \(32^2\) Greatest: \(4^7\)
Apply properties of integer exponents 53
Simplify each expression. Assume \(x\ne0\), \(y\ne0\), and \(z\ne0\). a) \((x^3)^4\cdot x^{-5}\) b) \(\frac{24y^6}{3y^2}\) c) \((-3a)^2\cdot a^3\) d) \(\frac{z^0\cdot z^7}{z^3}\)

Hints

- Multiply like bases by adding exponents and divide them by subtracting exponents. - For a power of a power, multiply the exponents. - A nonzero base raised to the zero power equals \(1\). - Apply an exponent to every factor inside parentheses.

Solution

1. \((x^3)^4=x^{12}\), so \(x^{12}\cdot x^{-5}=x^7\). 2. Divide the coefficients and subtract exponents: \(\frac{24y^6}{3y^2}=8y^4\). 3. \((-3a)^2=9a^2\), so \(9a^2\cdot a^3=9a^5\). 4. Since \(z^0=1\), \(\frac{z^0\cdot z^7}{z^3}=z^{7-3}=z^4\).

Answer

a) \(x^7\) b) \(8y^4\) c) \(9a^5\) d) \(z^4\)
Apply properties of integer exponents 54
Use exponent properties to simplify. Assume \(a\ne0\), \(b\ne0\), \(x\ne0\), and \(n\) is an integer. a) \(\frac{a^4\cdot b^{-2}}{a^{-1}\cdot b^3}\) b) \((0.2x^2)^3\cdot125x^{-6}\) c) \(\frac{x^{n+3}}{x^{n-1}}\)

Hints

- Apply the exponent rules to each base separately. - When dividing powers with the same base, subtract exponents. - A power outside parentheses applies to each factor inside. - An exponent containing a letter follows the same algebraic rules.

Solution

1. Subtract exponents for each base: \(a^{4-(-1)}b^{-2-3}=a^5b^{-5}=\frac{a^5}{b^5}\). 2. Evaluate the coefficient and exponents: \((0.2x^2)^3\cdot125x^{-6}=0.008x^6\cdot125x^{-6}=1\). 3. Subtract exponent expressions: \(\frac{x^{n+3}}{x^{n-1}}=x^{(n+3)-(n-1)}=x^4\).

Answer

a) \(\frac{a^5}{b^5}\) b) \(1\) c) \(x^4\)
Apply properties of integer exponents 55
Which of the following expressions are equivalent to \(16x^8\) for \(x \ne 0\)? Justify each choice by simplifying the expression. A: \((2x^2)^4\) B: \(8x^4 + 8x^4\) C: \(32x^9 \div (2x)\) D: \((4x^4)^2\) E: \(2 \cdot (2x^2)^3\)

Hints

- Simplify each expression until it is written in the form \(ax^n\). - Remember that adding like terms does not change the exponent. - An exponent outside parentheses applies to every factor inside the parentheses.

Solution

1. A: \((2x^2)^4 = 2^4(x^2)^4 = 16x^8\), so A is equivalent. 2. B: \(8x^4 + 8x^4 = 16x^4\), so B is not equivalent. 3. C: \(32x^9 \div (2x) = 16x^{9-1} = 16x^8\), so C is equivalent. 4. D: \((4x^4)^2 = 4^2(x^4)^2 = 16x^8\), so D is equivalent. 5. E: \(2 \cdot (2x^2)^3 = 2 \cdot 8x^6 = 16x^6\), so E is not equivalent.

Answer

A, C, and D are equivalent to \(16x^8\).
Apply properties of integer exponents 56
Simplify each expression and write the result without negative exponents. a) \(4^5\cdot4^{-7}\) b) \(\frac{3^{-2}}{3^2}\) c) \((2^{-3})^{-2}\) d) \(10^{-3}\cdot10^5\cdot10^{-2}\) e) \(\left(\frac{2}{5}\right)^{-2}\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract exponents when dividing powers with the same base. - A negative exponent indicates a reciprocal.

Solution

1. For a), add exponents: \(4^{5+(-7)}=4^{-2}=\frac{1}{16}\). 2. For b), subtract exponents: \(3^{-2-2}=3^{-4}=\frac{1}{81}\). 3. For c), multiply exponents: \(2^{(-3)\cdot(-2)}=2^6=64\). 4. For d), add exponents: \(10^{-3+5-2}=10^0=1\). 5. For e), take the reciprocal and use a positive exponent: \(\left(\frac{5}{2}\right)^2=\frac{25}{4}=6.25\).

Answer

a) \(\frac{1}{16}\) b) \(\frac{1}{81}\) c) \(64\) d) \(1\) e) \(\frac{25}{4}\)
Apply properties of integer exponents 57
Determine which expressions have the same value. Group them and justify each group by simplifying. \(A=\left(\frac{1}{3}\right)^{-2}\) \(B=3^{-2}\) \(C=\frac{1}{9}\) \(D=9\) \(E=\frac{3^5}{3^7}\) \(F=(-3)^2\)

Hints

- Simplify every expression to a numerical value. - Distinguish a negative base from a negative exponent. - Apply the quotient rule to expression \(E\).

Solution

1. \(A=\left(\frac{1}{3}\right)^{-2}=3^2=9\). 2. \(B=3^{-2}=\frac{1}{9}\). 3. \(C=\frac{1}{9}\) and \(D=9\). 4. \(E=3^{5-7}=3^{-2}=\frac{1}{9}\). 5. \(F=(-3)^2=9\). 6. Therefore, \(A,D,F\) have value \(9\), and \(B,C,E\) have value \(\frac{1}{9}\).

Answer

Value \(9\): \(A,D,F\) Value \(\frac{1}{9}\): \(B,C,E\)
Apply properties of integer exponents 58
Simplify and write the result without negative exponents: \(\frac{(x^2y^{-3})^{-2}}{x^{-1}y^4}\) Assume \(x\ne0\) and \(y\ne0\).

Hints

- Apply the outer exponent to both factors inside the parentheses. - Subtract exponents when dividing powers with the same base. - Move a factor with a negative exponent across the fraction bar.

Solution

1. Apply the power of a product and power of a power rules: \((x^2y^{-3})^{-2}=x^{-4}y^6\). 2. Divide powers with the same base: \(\frac{x^{-4}y^6}{x^{-1}y^4}=x^{-4-(-1)}y^{6-4}=x^{-3}y^2\). 3. Rewrite without negative exponents: \(x^{-3}y^2=\frac{y^2}{x^3}\).

Answer

\(\frac{y^2}{x^3}\)
Apply properties of integer exponents 59
Paul claims that for \(a\ne0\), \(\frac{a^3}{a^5}\) is equal to \(a^{-2}\). a) Expand the powers as repeated factors and simplify by canceling. b) Explain how your result from part a) relates to \(a^{-2}\). c) State a general rule for \(\frac{a^m}{a^n}\) that also applies when \(n>m\).

Hints

- Write each power as repeated multiplication. - Cancel matching factors in the numerator and denominator. - Recall the definition of a negative exponent.

Solution

1. Expand and cancel: \(\frac{a\cdot a\cdot a}{a\cdot a\cdot a\cdot a\cdot a}=\frac{1}{a^2}\). 2. By the definition of a negative exponent, \(a^{-2}=\frac{1}{a^2}\), so Paul’s claim is true. 3. For \(a\ne0\), the quotient rule is \(\frac{a^m}{a^n}=a^{m-n}\). When \(n>m\), the exponent \(m-n\) is negative.

Answer

a) \(\frac{1}{a^2}\) b) \(\frac{1}{a^2}=a^{-2}\), so the claim is true. c) For \(a\ne0\), \(\frac{a^m}{a^n}=a^{m-n}\).
Apply properties of integer exponents 60
Simplify each expression. Write each result as a single power with no fraction bar. Use negative exponents when needed. a) \(\frac{x^7x^{-3}}{x^2}\), where \(x\ne0\) b) \((y^{-2})^4y^5\), where \(y\ne0\) c) \(\frac{b^4}{b^{-2}}\), where \(b\ne0\)

Hints

- Add exponents when multiplying powers with the same base. - Multiply exponents when raising a power to a power. - When dividing, subtract the denominator exponent.

Solution

1. For a), add exponents in the numerator and subtract the denominator exponent: \(x^{7+(-3)-2}=x^2\). 2. For b), multiply exponents, then add: \(y^{(-2)\cdot4+5}=y^{-3}\). 3. For c), subtract the exponent in the denominator: \(b^{4-(-2)}=b^6\).

Answer

a) \(x^2\) b) \(y^{-3}\) c) \(b^6\)
Apply properties of integer exponents 61
Which expressions are equivalent to \(x^7\) for \(x\ne0\)? Select all that apply. A. \(x^3\cdot x^4\) B. \(\frac{x^{10}}{x^3}\) C. \((x^{-1})^{-7}\) D. \(x^7+x^7\) E. \(\frac{1}{x^{-7}}\) F. \(x^{14}\div x^2\) G. \(x^7\cdot x^0\)

Hints

- Apply the product, quotient, and power-of-a-power rules. - Distinguish addition of like terms from multiplication of powers. - Recall that \(x^0=1\) for \(x\ne0\).

Solution

1. \(A=x^{3+4}=x^7\). 2. \(B=x^{10-3}=x^7\). 3. \(C=x^{(-1)\cdot(-7)}=x^7\). 4. \(D=2x^7\), so it is not equivalent. 5. \(E=x^7\). 6. \(F=x^{14-2}=x^{12}\), so it is not equivalent. 7. Since \(x^0=1\), \(G=x^7\).

Answer

A, B, C, E, and G
Apply properties of integer exponents 62
Assume \(a\ne0\). Five of the following expressions are equivalent to \(a^{-6}\). Identify them and briefly explain why the other two are not equivalent. 1. \(a^{-2}\cdot a^{-4}\) 2. \((a^3)^{-2}\) 3. \(\frac{a^4}{a^{10}}\) 4. \((-a)^{-6}\) 5. \(\frac{1}{a^6}\) 6. \(-a^{-6}\) 7. \((a^{-3})^{-2}\)

Hints

- Simplify the exponent in each expression. - Pay attention to whether a negative sign is part of the base or outside the power. - An even exponent removes the sign of a nonzero base.

Solution

1. Expression 1 is \(a^{-2+(-4)}=a^{-6}\). 2. Expression 2 is \(a^{3\cdot(-2)}=a^{-6}\). 3. Expression 3 is \(a^{4-10}=a^{-6}\). 4. Expression 4 equals \(a^{-6}\) because the exponent is even. 5. Expression 5 equals \(a^{-6}\) by definition. 6. Expression 6 is the opposite of \(a^{-6}\), so it is not equivalent. 7. Expression 7 is \(a^{(-3)\cdot(-2)}=a^6\), so it is not equivalent.

Answer

Expressions 1, 2, 3, 4, and 5 are equivalent to \(a^{-6}\). Expressions 6 and 7 are not.
Apply properties of integer exponents 63
Assume \(b\ne0\) and \(x\ne0\). a) Find the integer \(n\) that makes \(\frac{b^n b^{-2}}{b^5}=b^3\) true for every nonzero \(b\). b) Rewrite \(4x^{-2}\) without negative exponents. Show which factor the exponent \(-2\) belongs to, and explain why your rewrite works for every nonzero \(x\). Then check your result at \(x=2\).

Hints

- Combine all powers of \(b\) before deciding which exponent is needed. - In part b), which part of the original expression is being raised to the negative power? - Can you rewrite that power as a fraction before checking any numbers?

Solution

1. Combine the left-hand exponents: \(\frac{b^{n-2}}{b^5}=b^{n-7}\). 2. For the identity to hold for every nonzero \(b\), \(n-7=3\), giving \(n=10\). 3. The exponent \(-2\) belongs to \(x\) only, so \(4x^{-2}=4\cdot\frac{1}{x^2}=\frac{4}{x^2}\) for all \(x\ne0\). 4. At \(x=2\), both \(4\cdot2^{-2}\) and \(\frac{4}{2^2}\) equal \(1\). This check is not the proof of equivalence; the exponent rule is.

Answer

a) \(n=10\) b) \(4x^{-2}=\frac{4}{x^2}\), since the negative exponent applies to \(x\), not \(4\). Both forms equal \(1\) at \(x=2\).
Apply properties of integer exponents 64
Assume all variables are nonzero. Simplify each expression and write the result without negative exponents. a) \(a^{-4}\cdot a^7\) b) \(b^2\div b^6\) c) \((c^{-2})^{-4}\) d) \(\frac{15x^3}{5x^8}\) e) \(\left(\frac{1}{y^3}\right)^{-2}\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract exponents when dividing. - Rewrite negative exponents as reciprocals at the end.

Solution

1. For a), \(a^{-4+7}=a^3\). 2. For b), \(b^{2-6}=b^{-4}=\frac{1}{b^4}\). 3. For c), \(c^{(-2)\cdot(-4)}=c^8\). 4. For d), \(\frac{15}{5}x^{3-8}=3x^{-5}=\frac{3}{x^5}\). 5. For e), \((y^{-3})^{-2}=y^6\).

Answer

a) \(a^3\) b) \(\frac{1}{b^4}\) c) \(c^8\) d) \(\frac{3}{x^5}\) e) \(y^6\)
Apply properties of integer exponents 65
Find the integer \(n\) that makes each equation true for **every nonzero value** of its letter base. a) \(z^n\cdot z^5=z^{-3}\) b) \((a^4)^n=\frac{1}{a^8}\) c) \(\frac{b^n}{b^{-2}}=b^5\) d) \(c^{-3}\cdot c^n=1\)

Hints

- Rewrite each side as a single power of its letter. - Turn a reciprocal into an equivalent negative power when useful. - For the last equation, what exponent gives a value of \(1\) for any nonzero base?

Solution

1. For a), \(n+5=-3\), so \(n=-8\). 2. For b), \(a^{4n}=a^{-8}\), so \(4n=-8\) and \(n=-2\). 3. For c), \(n-(-2)=5\), so \(n=3\). 4. For d), \(1=c^0\). Thus \(-3+n=0\) and \(n=3\).

Answer

a) \(n=-8\) b) \(n=-2\) c) \(n=3\) d) \(n=3\)
Apply properties of integer exponents 66
Assume \(a\ne0\) and \(b\ne0\). Simplify completely and write the result without negative exponents: \(\frac{(3a^{-2}b)^2a^5}{9b^3}\)

Hints

- Apply the outer exponent to every factor inside the parentheses. - Combine powers with the same base. - Rewrite any remaining negative exponent as a reciprocal.

Solution

1. Apply the exponent to each factor: \((3a^{-2}b)^2=9a^{-4}b^2\). 2. Multiply by \(a^5\): \(9a^{-4}b^2a^5=9ab^2\). 3. Divide by \(9b^3\): \(\frac{9ab^2}{9b^3}=ab^{-1}\). 4. Rewrite without a negative exponent: \(ab^{-1}=\frac{a}{b}\).

Answer

\(\frac{a}{b}\)
Apply properties of integer exponents 67
Assume \(k\ne0\) and \(a\ne0\). Lucas and Mia simplify \(\frac{k^5k^{-2}}{k^7}\). Lucas writes \(k^{5-2-7}=k^{-4}\). Mia writes \(\frac{k^3}{k^7}=\frac{1}{k^4}\). a) Explain why their results represent the same value. b) Simplify \(\frac{(a^2)^{-3}}{a^{-4}}\) and write the result without negative exponents.

Hints

- Use the definition of a negative exponent. - Multiply exponents when raising a power to a power. - Subtract exponents when dividing powers with the same base.

Solution

1. By the definition of negative exponents, \(k^{-4}=\frac{1}{k^4}\). Therefore, both students are correct. 2. For b), \((a^2)^{-3}=a^{-6}\). 3. Divide powers with the same base: \(a^{-6}\div a^{-4}=a^{-6-(-4)}=a^{-2}\). 4. Rewrite without a negative exponent: \(a^{-2}=\frac{1}{a^2}\).

Answer

a) Both are correct because \(k^{-4}=\frac{1}{k^4}\). b) \(\frac{1}{a^2}\)
Apply properties of integer exponents 68
Assume \(a\ne0\). Simplify and write the result without negative exponents: \(T=\frac{(3a)^2a^{-5}}{3a^{-1}}\)

Hints

- Square both the coefficient and the variable. - Simplify the numerator before dividing. - Rewrite the final negative exponent as a reciprocal.

Solution

1. Expand the power: \((3a)^2=9a^2\). 2. Combine the factors in the numerator: \(9a^2a^{-5}=9a^{-3}\). 3. Divide by \(3a^{-1}\): \(\frac{9a^{-3}}{3a^{-1}}=3a^{-3-(-1)}=3a^{-2}\). 4. Rewrite without a negative exponent: \(3a^{-2}=\frac{3}{a^2}\).

Answer

\(\frac{3}{a^2}\)
Apply properties of integer exponents 69
Assume \(x\ne0\) and \(y\ne0\). Simplify each expression. Write each result as a power with a negative exponent and no fraction bar. a) \(\frac{x^3x^{-7}}{x^{-2}}\) b) \((y^{-2})^{-3}y^{-10}\)

Hints

- Combine the numerator before dividing in part a). - Multiply exponents when raising a power to a power. - Keep careful track of subtracting a negative exponent.

Solution

1. For a), combine the numerator and then divide: \(x^{3+(-7)-(-2)}=x^{-2}\). 2. For b), raise the power to a power, then multiply: \(y^{(-2)\cdot(-3)+(-10)}=y^{6-10}=y^{-4}\).

Answer

a) \(x^{-2}\) b) \(y^{-4}\)
Apply properties of integer exponents 70
Evaluate without a calculator by applying exponent properties. a) \(3^5\cdot3^{-7}\) b) \(\left(\frac{1}{2}\right)^{-3}\cdot2^{-2}\) c) \(10^{-4}\div10^{-6}\) d) \((-5)^3\cdot(-5)^{-3}\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract exponents when dividing. - A negative exponent on a fraction reverses the fraction.

Solution

1. For a), \(3^{5+(-7)}=3^{-2}=\frac{1}{9}\). 2. For b), \(\left(\frac{1}{2}\right)^{-3}=2^3\), so \(2^3\cdot2^{-2}=2\). 3. For c), \(10^{-4-(-6)}=10^2=100\). 4. For d), \((-5)^{3+(-3)}=(-5)^0=1\).

Answer

a) \(\frac{1}{9}\) b) \(2\) c) \(100\) d) \(1\)
Apply properties of integer exponents 71
Simplify each expression. Give each result as a reduced fraction or an integer. a) \(8\cdot2^{-5}\) b) \(\left(\frac{3}{4}\right)^2\cdot\left(\frac{4}{3}\right)^{-1}\) c) \(0.25^{-1}\cdot4^{-2}\) d) \(\frac{7^2\cdot7^{-5}}{7^{-3}}\)

Hints

- Rewrite numbers using a common base when possible. - Convert a terminating decimal to a fraction before applying exponent rules. - A negative exponent on a fraction gives the reciprocal.

Solution

1. For a), write \(8=2^3\): \(2^3\cdot2^{-5}=2^{-2}=\frac{1}{4}\). 2. For b), \(\left(\frac{4}{3}\right)^{-1}=\frac{3}{4}\), so the product is \(\left(\frac{3}{4}\right)^3=\frac{27}{64}\). 3. For c), write \(0.25=\frac{1}{4}\): \(\left(\frac{1}{4}\right)^{-1}4^{-2}=4^1\cdot4^{-2}=\frac{1}{4}\). 4. For d), \(7^{2-5-(-3)}=7^0=1\).

Answer

a) \(\frac{1}{4}\) b) \(\frac{27}{64}\) c) \(\frac{1}{4}\) d) \(1\)
Apply properties of integer exponents 72
Complete each task about powers. a) Order the values from least to greatest: \(2^{-2}\), \((-2)^2\), \(2^0\), \((-2)^{-2}\). b) Find \(x\) so that \(5^x\cdot25=5^{-1}\). c) Evaluate mentally by grouping factors: \(2^9\cdot0.5^9\).

Hints

- Evaluate each power exactly before ordering. - Rewrite \(25\) as a power of \(5\). - Combine bases when the exponents are equal.

Solution

1. The values are \(2^{-2}=\frac{1}{4}\), \((-2)^2=4\), \(2^0=1\), and \((-2)^{-2}=\frac{1}{4}\). Therefore, \(2^{-2}=(-2)^{-2}<2^0<(-2)^2\). 2. For b), write \(25=5^2\). Then \(x+2=-1\), so \(x=-3\). 3. For c), use the common exponent: \(2^9\cdot0.5^9=(2\cdot0.5)^9=1\).

Answer

a) \(2^{-2}=(-2)^{-2}<2^0<(-2)^2\) b) \(x=-3\) c) \(1\)
Apply properties of integer exponents 73
Assume all variables are nonzero. Simplify using exponent properties and write each result without negative exponents. a) \(a^5\cdot a^{-9}\) b) \(x^{-3}\div x^{-5}\) c) \((y^{-2})^4\) d) \(b^2\cdot b^{-2}\)

Hints

- Add exponents when multiplying and subtract them when dividing. - Multiply exponents when raising a power to a power. - Rewrite negative exponents as reciprocals.

Solution

1. For a), \(a^{5+(-9)}=a^{-4}=\frac{1}{a^4}\). 2. For b), \(x^{-3-(-5)}=x^2\). 3. For c), \(y^{(-2)\cdot4}=y^{-8}=\frac{1}{y^8}\). 4. For d), \(b^{2+(-2)}=b^0=1\).

Answer

a) \(\frac{1}{a^4}\) b) \(x^2\) c) \(\frac{1}{y^8}\) d) \(1\)
Apply properties of integer exponents 74
Assume all variables are nonzero. Simplify and write each result as a fraction or a power with a positive exponent. a) \(\frac{z^{-3}z^7}{z^2}\) b) \(\left(\frac{x^2}{y}\right)^{-3}\) c) \((3a^{-2})^2a^5\)

Hints

- Combine powers with the same base. - A negative exponent on a fraction reverses the fraction. - Apply an exponent to every factor inside parentheses.

Solution

1. For a), \(z^{-3+7-2}=z^2\). 2. For b), take the reciprocal and cube: \(\left(\frac{y}{x^2}\right)^3=\frac{y^3}{x^6}\). 3. For c), \((3a^{-2})^2a^5=9a^{-4}a^5=9a\).

Answer

a) \(z^2\) b) \(\frac{y^3}{x^6}\) c) \(9a\)
Apply properties of integer exponents 75
Assume all variables are nonzero. Simplify completely. Pay close attention to signs and negative exponents. a) \(\frac{4x^{-2}}{2x^{-4}}\) b) \((x^{-2}y^3)^2(x^3y^{-4})\) c) \((-a^2)^{-3}a^7\)

Hints

- Divide coefficients and subtract exponents in part a). - Apply each outer exponent before combining powers with the same base. - In part c), decide whether the odd exponent preserves or changes the negative sign.

Solution

1. For a), divide the coefficients and subtract exponents: \(\frac{4x^{-2}}{2x^{-4}}=2x^{-2-(-4)}=2x^2\). 2. For b), \((x^{-2}y^3)^2(x^3y^{-4})=x^{-4}y^6x^3y^{-4}=x^{-1}y^2=\frac{y^2}{x}\). 3. For c), \((-a^2)^{-3}=-a^{-6}\) because the exponent is odd. Then \(-a^{-6}a^7=-a\).

Answer

a) \(2x^2\) b) \(\frac{y^2}{x}\) c) \(-a\)
Apply properties of integer exponents 76
Maria made an error in each solution. Describe each error and give the correct result. Assume \(x\ne0\) and \(a\ne0\). a) \(3^{-2}=-9\) b) \(\frac{1}{x^5}=x^5\) c) \(2a^{-3}=\frac{1}{2a^3}\)

Hints

- A negative exponent creates a reciprocal. - Moving a factor across a fraction bar changes the exponent’s sign. - An exponent applies only to the base immediately before it unless parentheses show otherwise.

Solution

1. In a), a negative exponent means a reciprocal, not a negative value: \(3^{-2}=\frac{1}{3^2}=\frac{1}{9}\). 2. In b), moving a power across the fraction bar changes the sign of the exponent: \(\frac{1}{x^5}=x^{-5}\). 3. In c), the exponent applies only to \(a\), not to the coefficient \(2\): \(2a^{-3}=\frac{2}{a^3}\).

Answer

a) A negative exponent means a reciprocal, not a negative value: \(3^{-2}=\frac{1}{9}\). b) Moving a power across the fraction bar changes the exponent sign: \(\frac{1}{x^5}=x^{-5}\). c) The exponent applies only to \(a\), not to \(2\): \(2a^{-3}=\frac{2}{a^3}\).
Apply properties of integer exponents 77
Assume \(y\ne0\). Consider \(T=\frac{y^{-3}y^5}{y^{-2}}\). Lucas claims the result is \(y^0=1\). Sarah claims the result is \(y^4\). Determine who is correct and justify your answer step by step.

Hints

- Add exponents when multiplying powers with the same base. - Subtract the denominator exponent when dividing. - Be careful when subtracting a negative number.

Solution

1. Simplify the numerator: \(y^{-3}y^5=y^{-3+5}=y^2\). 2. Divide by \(y^{-2}\): \(y^{2-(-2)}=y^4\). 3. Sarah is correct. Lucas incorrectly treated subtraction of \(-2\) as subtraction of \(2\).

Answer

Sarah is correct; the expression simplifies to \(y^4\).
Apply properties of integer exponents 78
For any nonzero base \(a\) and integer exponent \(n\), determine whether each statement is true or false. Justify your decision by simplifying the left side. a) \(a^n a^{-n}=1\) b) \((a^{-1})^n=\frac{1}{a^n}\) c) \(\frac{a^n}{a^{n+2}}=a^2\)

Hints

- Apply the product, quotient, and power-of-a-power rules. - A nonzero base raised to the zero power equals \(1\). - Distribute a subtraction sign across grouped terms in an exponent.

Solution

1. For a), \(a^n a^{-n}=a^{n-n}=a^0=1\), so the statement is true. 2. For b), \((a^{-1})^n=a^{-n}=\frac{1}{a^n}\), so the statement is true. 3. For c), \(\frac{a^n}{a^{n+2}}=a^{n-(n+2)}=a^{-2}=\frac{1}{a^2}\), so the statement is false.

Answer

a) True. b) True. c) False; the left side equals \(\frac{1}{a^2}\).
Apply properties of integer exponents 79
Assume all variables are nonzero. Simplify completely and write each result without negative exponents. a) \((3y^2)^{-2}\cdot27y^5\) b) \(\left(\frac{k}{2}\right)^{-3}k^2\) c) \(\frac{m^{-4}}{(m^{-2})^3}\)

Hints

- A negative exponent on a fraction reverses the fraction. - Apply an exponent to every factor in parentheses. - Subtract exponents carefully when dividing.

Solution

1. For a), \((3y^2)^{-2}=\frac{1}{9y^4}\), so \(\frac{27y^5}{9y^4}=3y\). 2. For b), \(\left(\frac{k}{2}\right)^{-3}=\left(\frac{2}{k}\right)^3=\frac{8}{k^3}\), so the product is \(\frac{8}{k}\). 3. For c), \((m^{-2})^3=m^{-6}\), so \(m^{-4-(-6)}=m^2\).

Answer

a) \(3y\) b) \(\frac{8}{k}\) c) \(m^2\)
Apply properties of integer exponents 80
Assume all variables are nonzero. Simplify and write each result without negative exponents. a) \(\frac{(u^3v^{-2})^{-1}}{u^{-4}v}\) b) \(\left(\frac{2}{x^2}\right)^{-2}(xy^0)^{-3}\)

Hints

- Simplify the numerator and denominator separately. - Recall that a nonzero number to the zero power equals \(1\). - Rewrite negative powers before combining factors.

Solution

1. For a), \((u^3v^{-2})^{-1}=u^{-3}v^2\). Dividing by \(u^{-4}v\) gives \(u^{-3-(-4)}v^{2-1}=uv\). 2. For b), \(\left(\frac{2}{x^2}\right)^{-2}=\frac{x^4}{4}\), and \((xy^0)^{-3}=x^{-3}\) because \(y^0=1\). 3. Multiply: \(\frac{x^4}{4}x^{-3}=\frac{x}{4}\).

Answer

a) \(uv\) b) \(\frac{x}{4}\)
Apply properties of integer exponents 81
Assume all variables are nonzero. Simplify each expression as far as possible. a) \(\left(\frac{x}{y}\right)^4\left(\frac{y}{x}\right)^2\) b) \(\left(\frac{a}{b}\right)^2\div\frac{a^3}{b}\) c) \(\left(\frac{m}{n}\right)^{-2}\cdot\frac{m^2}{n^2}\)

Hints

- Apply powers to both numerator and denominator. - Rewrite division as multiplication by the reciprocal. - A negative exponent on a fraction reverses the fraction.

Solution

1. For a), \(\frac{x^4}{y^4}\cdot\frac{y^2}{x^2}=\frac{x^2}{y^2}\), where \(x\ne0\) and \(y\ne0\). 2. For b), \(\frac{a^2}{b^2}\cdot\frac{b}{a^3}=\frac{1}{ab}\), where \(a\ne0\) and \(b\ne0\). 3. For c), \(\left(\frac{n}{m}\right)^2\cdot\frac{m^2}{n^2}=1\), where \(m\ne0\) and \(n\ne0\).

Answer

a) \(\frac{x^2}{y^2}\), where \(x\ne0\) and \(y\ne0\) b) \(\frac{1}{ab}\), where \(a\ne0\) and \(b\ne0\) c) \(1\), where \(m\ne0\) and \(n\ne0\)
Apply properties of integer exponents 82
Assume all variables are nonzero. Simplify and write each result without negative exponents. a) \(\left(\frac{2a}{b^2}\right)^3\left(\frac{b}{a}\right)^4\) b) \(\left(\left(\frac{x}{y}\right)^{-2}\right)^3\div\left(\frac{y}{x}\right)^4\)

Hints

- Apply each exponent to the coefficient and every variable factor. - Multiply exponents when raising a power to a power. - Combine powers with the same fractional base.

Solution

1. For a), \(\left(\frac{2a}{b^2}\right)^3=\frac{8a^3}{b^6}\) and \(\left(\frac{b}{a}\right)^4=\frac{b^4}{a^4}\). 2. Multiply and simplify: \(\frac{8a^3b^4}{b^6a^4}=\frac{8}{ab^2}\). 3. For b), \(\left(\left(\frac{x}{y}\right)^{-2}\right)^3=\left(\frac{x}{y}\right)^{-6}=\left(\frac{y}{x}\right)^6\). 4. Divide powers with the same base: \(\left(\frac{y}{x}\right)^{6-4}=\frac{y^2}{x^2}\).

Answer

a) \(\frac{8}{ab^2}\) b) \(\frac{y^2}{x^2}\)
Apply properties of integer exponents 83
Complete the pattern of powers of \(3\). \(3^3=27\) \(3^2=9\) \(3^1=3\) \(3^0=\text{?}\) \(3^{-1}=\text{?}\) \(3^{-2}=\text{?}\) a) Fill in the three missing values by continuing the pattern. b) Explain why the pattern supports \(3^0=1\) and \(3^{-2}=\frac{1}{3^2}\). c) State the corresponding rule for \(a^{-n}\), where \(a\ne0\) and \(n\) is a positive integer.

Hints

- Compare each value with the value immediately above it. - Ask what operation matches a decrease of \(1\) in the exponent. - Express the values below \(3^0\) as reciprocals of positive powers.

Solution

1. Each time the exponent decreases by \(1\), divide the previous value by \(3\). 2. Therefore, \(3^0=3\div3=1\), \(3^{-1}=1\div3=\frac13\), and \(3^{-2}=\frac13\div3=\frac19\). 3. Since \(3^2=9\), the value \(3^{-2}=\frac19\) is \(\frac{1}{3^2}\). 4. The same pattern gives \(a^{-n}=\frac{1}{a^n}\) for every nonzero \(a\) and positive integer \(n\).

Answer

a) \(3^0=1\), \(3^{-1}=\frac13\), and \(3^{-2}=\frac19\) b) Decreasing the exponent by \(1\) divides the value by \(3\), so \(3^0=1\) and \(3^{-2}=\frac19=\frac{1}{3^2}\). c) \(a^{-n}=\frac{1}{a^n}\)
Apply properties of integer exponents 84
Simplify each expression and write the result without negative exponents. a) \(x^3x^{-5}\), where \(x\ne0\) b) \(\frac{a^{-2}}{a^{-4}}\), where \(a\ne0\) c) \((y-1)^2(y-1)^{-3}\), where \(y\ne1\) d) \(2z^{-3}z\), where \(z\ne0\)

Hints

- Treat a repeated binomial as a single base. - Add exponents when multiplying and subtract them when dividing. - Rewrite a negative exponent as a reciprocal.

Solution

1. For a), \(x^{3-5}=x^{-2}=\frac{1}{x^2}\). 2. For b), \(a^{-2-(-4)}=a^2\). 3. For c), \((y-1)^{2-3}=(y-1)^{-1}=\frac{1}{y-1}\). 4. For d), \(2z^{-3+1}=2z^{-2}=\frac{2}{z^2}\).

Answer

a) \(\frac{1}{x^2}\) b) \(a^2\) c) \(\frac{1}{y-1}\) d) \(\frac{2}{z^2}\)
Apply properties of integer exponents 85
Assume all variables are nonzero. Simplify and write each result without negative exponents. a) \((2a)^{-3}\cdot8a^4\) b) \(\frac{x^{-2}y^2}{(xy)^{-1}}\) c) \(\left(\frac{b^2}{3}\right)^{-2}b^4\)

Hints

- Apply a negative exponent to every factor inside parentheses. - Subtract exponents when dividing powers with the same base. - Recall that a nonzero base to the zero power equals \(1\).

Solution

1. For a), \((2a)^{-3}=\frac{1}{8}a^{-3}\), so the product is \(a\). 2. For b), \((xy)^{-1}=x^{-1}y^{-1}\). Dividing gives \(x^{-2-(-1)}y^{2-(-1)}=x^{-1}y^3=\frac{y^3}{x}\). 3. For c), \(\left(\frac{b^2}{3}\right)^{-2}=9b^{-4}\), so multiplying by \(b^4\) gives \(9\).

Answer

a) \(a\) b) \(\frac{y^3}{x}\) c) \(9\)
Apply properties of integer exponents 86
Assume \(u\ne0\), \(v\ne0\), and \(x\ne0\). a) Simplify \(\frac{(u^{-1}v^2)^3}{u^{-4}v^5}\). b) Find the integer \(n\) so that \(\frac{x^n}{x^{-3}}=x^2\) is true for every nonzero \(x\). c) Explain without calculating why \((-3)^{-2}\) is positive but \(-3^{-2}\) is negative.

Hints

- Apply the outside exponent to each factor in the product. - Compare the exponents after simplifying part b). - Check which number is the base of the power in each expression in part c).

Solution

1. The numerator in a) is \(u^{-3}v^6\). Dividing gives \(u^{-3-(-4)}v^{6-5}=uv\). 2. For b), \(\frac{x^n}{x^{-3}}=x^{n+3}\). An identity for all nonzero \(x\) requires \(n+3=2\), so \(n=-1\). 3. In \((-3)^{-2}\), the negative sign is part of the base and the even power gives a positive result. In \(-3^{-2}\), the negative sign is outside the power.

Answer

a) \(uv\) b) \(n=-1\) c) \((-3)^{-2}\) is positive because the negative base is squared. In \(-3^{-2}\), the minus sign stays outside the power, so the result is negative.
Apply properties of integer exponents 87
Evaluate or simplify without a calculator. Assume \(x\ne0\) in part b. a) \((-5)^2\) and \(-5^2\) b) \(\frac{x^6}{x^2\cdot x^3}\) c) \((2a^3)^4\) d) \(10^3\cdot10^{-5}\)

Hints

- Determine whether the negative sign is part of the base. - Add exponents when multiplying like bases and subtract them when dividing. - Multiply exponents for a power of a power. - Rewrite a negative exponent as a reciprocal.

Solution

1. \((-5)^2=25\), while \(-5^2=-(5^2)=-25\). 2. The denominator is \(x^2\cdot x^3=x^5\), so \(\frac{x^6}{x^5}=x\). 3. \((2a^3)^4=2^4(a^3)^4=16a^{12}\). 4. \(10^3\cdot10^{-5}=10^{-2}=\frac{1}{100}=0.01\).

Answer

a) \(25\) and \(-25\) b) \(x\) c) \(16a^{12}\) d) \(0.01\)
Apply properties of integer exponents 88
Use exponent properties. Assume \(x\ne0\) in part b. a) Evaluate and compare \(2^{-3}\) and \(-2^3\). b) Simplify \(\frac{(x^2)^3}{x^4\cdot x^{-1}}\). c) Evaluate \(\frac{15^3}{5^3}\) using the quotient property. d) Find \(x\) if \(2^x=\frac{1}{32}\).

Hints

- A negative exponent produces a reciprocal. - Rewrite \(32\) as a power of \(2\). - Use the quotient property when two powers have the same exponent.

Solution

1. \(2^{-3}=\frac{1}{8}=0.125\), while \(-2^3=-8\). Therefore, \(2^{-3}>-2^3\). 2. \((x^2)^3=x^6\), and \(x^4\cdot x^{-1}=x^3\). Thus \(\frac{x^6}{x^3}=x^3\). 3. \(\frac{15^3}{5^3}=\left(\frac{15}{5}\right)^3=3^3=27\). 4. Since \(\frac{1}{32}=2^{-5}\), matching exponents gives \(x=-5\).

Answer

a) \(2^{-3}=0.125>-8=-2^3\) b) \(x^3\) c) \(27\) d) \(x=-5\)
Apply properties of integer exponents 89
Use exponent properties. Assume \(a\ne0\) and \(b\ne0\) in part a. a) Simplify \(\frac{18a^5b^{-2}}{3(ab)^2}\). Write the answer without negative exponents. b) Find \(n\) if \(\frac{5^8}{5^n}=125\). c) Show that \(\frac{2^k\cdot2^{k+1}}{4^k}\) has the same numerical value for every positive integer \(k\), and find that value.

Hints

- Expand powers of products before combining like bases. - Rewrite \(125\) as a power of \(5\). - In part c, rewrite every power using base \(2\).

Solution

1. Expand the denominator: \(3(ab)^2=3a^2b^2\). Then \(\frac{18a^5b^{-2}}{3a^2b^2}=6a^3b^{-4}=\frac{6a^3}{b^4}\). 2. Since \(125=5^3\), \(5^{8-n}=5^3\). Therefore, \(8-n=3\) and \(n=5\). 3. Rewrite \(4^k=(2^2)^k=2^{2k}\). The numerator is \(2^{2k+1}\), so the quotient is \(2^{2k+1-2k}=2\).

Answer

a) \(\frac{6a^3}{b^4}\) b) \(n=5\) c) \(2\)
Apply properties of integer exponents 90
Karim simplifies \(4x^2 \cdot (3x)^2\) as follows: \(4x^2 \cdot (3x)^2 = 4x^2 \cdot 3x^2 = 12x^4\) Explain the error in the first step and find the correct result.

Hints

- Determine every factor to which the exponent applies. - Check whether the exponent applies to the entire quantity in parentheses. - Treat the numerical coefficient and the power of \(x\) consistently.

Solution

1. The exponent applies to both factors inside the parentheses. Karim squared \(x\) but did not square \(3\). 2. Correctly expand the power: \((3x)^2 = 3^2x^2 = 9x^2\). 3. Multiply: \(4x^2 \cdot 9x^2 = 36x^4\).

Answer

Karim failed to square the coefficient \(3\). The correct result is \(36x^4\).
Apply properties of integer exponents 91
Let \(T_1 = (2a)^3\) and \(T_2 = 2a^3\). a) Evaluate both expressions when \(a = 3\). b) Use the order of operations to explain why the results are different.

Hints

- Substitute \(a = 3\) and follow the order of operations. - Parentheses identify the complete base of a power. - Exponents are evaluated before multiplication when there are no grouping symbols.

Solution

1. Substitute \(a = 3\): \(T_1 = (2 \cdot 3)^3 = 6^3 = 216\). 2. For the second expression, \(T_2 = 2 \cdot 3^3 = 2 \cdot 27 = 54\). 3. In \(T_1\), the parentheses make \(2a\) the entire base, so the product is cubed. In \(T_2\), the exponent applies only to \(a\), and multiplication by \(2\) occurs afterward.

Answer

a) \(T_1 = 216\) and \(T_2 = 54\) b) In \(T_1\), the entire product \(2a\) is cubed. In \(T_2\), only \(a\) is cubed before multiplying by \(2\).
Apply properties of integer exponents 92
Assume \(a\ne0\). Simplify and write the result without a fraction bar, using a negative exponent: \(\frac{a^{-3}(a^2)^{-2}}{a^{-5}}\)

Hints

- Multiply exponents when raising a power to a power. - Add exponents in the numerator. - Subtract the denominator exponent carefully.

Solution

1. Raise the power to a power: \((a^2)^{-2}=a^{-4}\). 2. Combine the numerator: \(a^{-3}a^{-4}=a^{-7}\). 3. Divide: \(a^{-7}\div a^{-5}=a^{-7-(-5)}=a^{-2}\).

Answer

\(a^{-2}\)
Apply properties of integer exponents 93
Simplify each expression. a) Evaluate \((-4)^2\), \(-4^2\), and \((-2)^3\). b) Simplify \(x^2 \cdot x^5 \cdot x\). c) Simplify \((y^8 \div y^3) \cdot y^2\) for \(y \ne 0\).

Hints

- Determine whether a negative sign is inside or outside the base. - A variable with no written exponent has exponent \(1\). - Add exponents when multiplying powers with the same base. - Subtract exponents when dividing powers with the same nonzero base.

Solution

1. a) \((-4)^2 = 16\), \(-4^2 = -(4^2) = -16\), and \((-2)^3 = -8\). 2. b) Since \(x = x^1\), add the exponents: \(x^{2+5+1} = x^8\). 3. c) First divide: \(y^8 \div y^3 = y^{8-3} = y^5\). Then multiply: \(y^5 \cdot y^2 = y^7\).

Answer

a) \(16, -16, -8\) b) \(x^8\) c) \(y^7\)
Apply properties of integer exponents 94
Find the rational number \(x\) that makes the equation true: \(10^4\cdot10^x=0.01\)

Hints

- Rewrite the decimal as a power of \(10\). - Add exponents when multiplying powers with the same base. - Equal powers with the same base have equal exponents.

Solution

1. Write \(0.01\) as a power of \(10\): \(0.01=10^{-2}\). 2. Combine the powers on the left: \(10^4\cdot10^x=10^{4+x}\). 3. Set the exponents equal: \(4+x=-2\). 4. Solve to get \(x=-6\).

Answer

\(x=-6\)
Apply properties of integer exponents 95
Find the rational number \(n\) that makes the equation true: \(2^n\cdot8^{-1}=\frac{1}{32}\)

Hints

- Rewrite \(8\) and \(32\) as powers of \(2\). - Apply the power-of-a-power rule. - Compare the exponents after the bases match.

Solution

1. Write every term as a power of \(2\): \(8^{-1}=(2^3)^{-1}=2^{-3}\) and \(\frac{1}{32}=2^{-5}\). 2. Combine the left side: \(2^n\cdot2^{-3}=2^{n-3}\). 3. Set exponents equal: \(n-3=-5\). 4. Solve to get \(n=-2\).

Answer

\(n=-2\)
Apply properties of integer exponents 96
Find all rational numbers \(a\) that satisfy \(25a^{-2}=4\).

Hints

- Rewrite the negative exponent as a reciprocal. - Isolate \(a^2\). - Remember both square roots of a positive number.

Solution

1. Rewrite the negative exponent: \(25a^{-2}=\frac{25}{a^2}\). 2. Solve \(\frac{25}{a^2}=4\): \(25=4a^2\), so \(a^2=\frac{25}{4}\). 3. Taking both square roots gives \(a=\pm\frac{5}{2}\).

Answer

\(a=-\frac{5}{2}\) or \(a=\frac{5}{2}\)
Apply properties of integer exponents 97
Assume \(x\ne0\). Simplify and write the result as a single power with no fraction bar: \(\frac{x^4x^{-7}}{(x^{-2})^2}\)

Hints

- Simplify the numerator and denominator separately. - Multiply exponents in the denominator. - Subtract the denominator exponent when dividing.

Solution

1. Simplify the numerator: \(x^4x^{-7}=x^{-3}\). 2. Simplify the denominator: \((x^{-2})^2=x^{-4}\). 3. Divide: \(x^{-3}\div x^{-4}=x^{-3-(-4)}=x\).

Answer

\(x\)
Apply properties of integer exponents 98
Assume \(a\ne0\) and \(b\ne0\). Simplify and write the result without negative exponents: \(\left(\frac{a^2}{b}\right)^{-2}(ab^3)^{-1}\)

Hints

- A negative exponent on a fraction reverses the fraction. - Apply the exponent to every factor in a product. - Cancel common powers at the end.

Solution

1. Reverse the first fraction and square: \(\left(\frac{a^2}{b}\right)^{-2}=\frac{b^2}{a^4}\). 2. Rewrite the second factor: \((ab^3)^{-1}=\frac{1}{ab^3}\). 3. Multiply: \(\frac{b^2}{a^4}\cdot\frac{1}{ab^3}=\frac{1}{a^5b}\).

Answer

\(\frac{1}{a^5b}\)
Apply properties of integer exponents 99
Simplify each expression using exponent properties, then find its value. a) \(0.25^{-3}\cdot4^{-5}\cdot2^4\) b) \((-6)^3\div3^3\cdot(-2)^{-1}\)

Hints

- Rewrite the decimal as a fraction or a power with a useful base. - Combine powers with the same exponent when possible. - Pay attention to whether a negative sign is part of the base.

Solution

1. For a), \(0.25=4^{-1}\), so \(0.25^{-3}=4^3\), and \(2^4=4^2\). Thus \(4^{3-5+2}=4^0=1\). 2. For b), \((-6)^3\div3^3=(-2)^3\). Then \((-2)^3\cdot(-2)^{-1}=(-2)^2=4\).

Answer

a) \(1\) b) \(4\)
Apply properties of integer exponents 100
Evaluate using exponent properties. Show intermediate steps. \(\frac{12^3\cdot2^{-4}}{3^2\cdot2^{-1}}\)

Hints

- Factor \(12\) into powers of \(2\) and \(3\). - Simplify the numerator first. - Subtract the denominator exponents when dividing.

Solution

1. Factor \(12=3\cdot2^2\): \(12^3=3^3\cdot2^6\). 2. The numerator becomes \(3^3\cdot2^{6-4}=3^3\cdot2^2\). 3. Divide by the denominator: \(3^{3-2}\cdot2^{2-(-1)}=3\cdot2^3\). 4. Evaluate: \(3\cdot8=24\).

Answer

\(24\)
Apply properties of integer exponents 101
For every nonzero \(x\), define \(E(x)=3x^{-2}\). a) Rewrite \(E(x)\) using positive exponents only. b) Find \(E(1)\), \(E(2)\), and \(E(4)\) using your rewrite. c) What happens to \(E(x)\) each time \(x\) is doubled? Explain. d) Why is \(E(x)\) always positive?

Hints

- Rewrite the negative exponent as a reciprocal before substituting. - Compare the denominator when the input doubles. - What can you say about the square of a nonzero number?

Solution

1. Since \(x^{-2}=\frac{1}{x^2}\), \(E(x)=\frac{3}{x^2}\). 2. Substitute: \(E(1)=3\), \(E(2)=\frac{3}{4}\), and \(E(4)=\frac{3}{16}\). 3. Replacing \(x\) by \(2x\) multiplies its square by \(4\), so \(E(x)\) is divided by \(4\). 4. The numerator \(3\) is positive and \(x^2>0\) whenever \(x\ne0\), so \(E(x)>0\).

Answer

a) \(E(x)=\frac{3}{x^2}\) b) \(E(1)=3\), \(E(2)=\frac{3}{4}\), \(E(4)=\frac{3}{16}\) c) The value is divided by \(4\) each time \(x\) is doubled because \((2x)^2=4x^2\), making the denominator four times as large. d) Both \(3\) and \(x^2\) are positive for nonzero \(x\).
Apply properties of integer exponents 102
Simplify and write each answer without negative exponents. Assume \(x\ne0\), \(y\ne0\), \(z\ne0\), and \(a\ne0\). a) \(x^4\cdot x^{-6}\) b) \(\frac{y^{-2}}{y^3}\) c) \((-2z)^{-3}\) d) \((a^2\cdot a^{-3})^2\)

Hints

- Add exponents when multiplying like bases and subtract them when dividing. - Rewrite a negative exponent as a reciprocal. - Simplify inside parentheses before applying an outside exponent.

Solution

1. \(x^4\cdot x^{-6}=x^{-2}=\frac{1}{x^2}\). 2. \(\frac{y^{-2}}{y^3}=y^{-5}=\frac{1}{y^5}\). 3. \((-2z)^{-3}=\frac{1}{(-2z)^3}=-\frac{1}{8z^3}\). 4. \((a^2\cdot a^{-3})^2=(a^{-1})^2=a^{-2}=\frac{1}{a^2}\).

Answer

a) \(\frac{1}{x^2}\) b) \(\frac{1}{y^5}\) c) \(-\frac{1}{8z^3}\) d) \(\frac{1}{a^2}\)
Apply properties of integer exponents 103
Simplify and write each answer without negative exponents. Assume \(a\ne0\), \(b\ne0\), \(x\ne0\), and \(y\ne0\). a) \(\frac{15a^4\cdot a^{-7}}{3a^{-2}}\) b) \((2b^{-2})^3\cdot(b^2)^2\) c) \(\left(\frac{x}{y^2}\right)^{-2}\cdot x^{-1}\)

Hints

- Apply an outside exponent to every factor in parentheses. - A negative exponent reverses a fraction. - Combine like bases only after expanding the powers.

Solution

1. Divide coefficients and combine exponents: \(5a^{4-7-(-2)}=5a^{-1}=\frac{5}{a}\). 2. \((2b^{-2})^3=8b^{-6}\) and \((b^2)^2=b^4\). Their product is \(8b^{-2}=\frac{8}{b^2}\). 3. \(\left(\frac{x}{y^2}\right)^{-2}=\frac{y^4}{x^2}\). Multiplying by \(x^{-1}\) gives \(\frac{y^4}{x^3}\).

Answer

a) \(\frac{5}{a}\) b) \(\frac{8}{b^2}\) c) \(\frac{y^4}{x^3}\)
Apply properties of integer exponents 104
A jeweler makes beads shaped like regular tetrahedra. Their volume is \(V=\frac{\sqrt{2}}{12}a^3\), where \(a\) is the edge length. a) The edge length changes from \(10\,\text{mm}\) to \(12\,\text{mm}\). By what percent does the volume increase? b) By what factor does the volume change if the edge length is tripled? Explain using the formula.

Hints

- What part of the volume formula stays the same when the edge length changes? - Compare the new and old volumes using a ratio before finding a percent increase. - How does replacing \(a\) with \(3a\) affect the power in the formula?

Solution

1. The fixed factor \(\frac{\sqrt{2}}{12}\) cancels in the ratio of volumes: \(\frac{V_{12}}{V_{10}}=\frac{12^3}{10^3}=\left(\frac{12}{10}\right)^3=1.728\). 2. The percent increase is \((1.728-1)\cdot100\%=72.8\%\). 3. If the edge length triples, \(V_{\text{new}}=\frac{\sqrt{2}}{12}(3a)^3=27\cdot\frac{\sqrt{2}}{12}a^3=27V_{\text{old}}\).

Answer

a) \(72.8\%\) increase, since \(\left(\frac{12}{10}\right)^3=1.728\). b) The volume is multiplied by \(27\), because \(\frac{\sqrt{2}}{12}(3a)^3=27\cdot\frac{\sqrt{2}}{12}a^3\).
Apply properties of integer exponents 105
Use exponent properties to simplify. Assume \(a\ne0\), \(b\ne0\), \(x\ne0\), and \(n\in\mathbb{Z}\). a) \(\frac{a^{2n+1}\cdot a^{n-2}}{a^{3n-1}}\) b) \((2b^3)^{-2}\cdot4b^6\) c) \(\frac{(-x)^4\cdot x^{-2}}{x^5}\)

Hints

- Combine variable expressions in exponents just as you combine numerical exponents. - A zero exponent gives \(1\) for a nonzero base. - Determine the sign before combining powers.

Solution

1. The numerator exponent in part a is \((2n+1)+(n-2)=3n-1\). Dividing by \(a^{3n-1}\) gives \(a^0=1\). 2. \((2b^3)^{-2}=\frac{1}{4}b^{-6}\). Multiplying by \(4b^6\) gives \(1\). 3. Since \((-x)^4=x^4\), the quotient is \(x^{4-2-5}=x^{-3}=\frac{1}{x^3}\).

Answer

a) \(1\) b) \(1\) c) \(\frac{1}{x^3}\)
Apply properties of integer exponents 106
Answer each question by expanding powers as products. 1) Is \(5a^2\) equivalent to \((5a)^2\)? Explain. 2) Lucía says, “When I multiply \(x^2\) by \(x^4\), I get \(x^8\) because \(2 \cdot 4 = 8\).” Evaluate the claim. 3) Rewrite \(z \cdot z \cdot w \cdot z \cdot w \cdot w\) using exponents.

Hints

- Expand each power as repeated multiplication. - Identify whether a coefficient is inside or outside the base. - Count how many times each variable appears as a factor.

Solution

1. \(5a^2 = 5 \cdot a \cdot a\), while \((5a)^2 = (5a)(5a) = 25a^2\). The expressions are not equivalent. 2. \(x^2 \cdot x^4\) contains six factors of \(x\), so it equals \(x^6\). The claim is false because exponents are added when powers with the same base are multiplied. 3. The product has three factors of \(z\) and three factors of \(w\), so it is \(z^3w^3\).

Answer

1) No; \(5a^2\) and \((5a)^2 = 25a^2\) are not equivalent. 2) False; \(x^2 \cdot x^4 = x^6\). 3) \(z^3w^3\)
Apply properties of integer exponents 107
Complete each task. 1) Write \((3y)(3y)\) using exponent notation, first with parentheses and then without parentheses. 2) Evaluate \(2x^3\) and \((2x)^3\) when \(x = 3\). 3) Rewrite \(m \cdot m \cdot m + n \cdot n\) using exponents.

Hints

- A power outside parentheses applies to every factor inside. - Follow the order of operations when substituting. - Count repeated factors separately in each term.

Solution

1. The repeated factor is \(3y\), so \((3y)(3y) = (3y)^2 = 9y^2\). 2. \(2x^3 = 2 \cdot 3^3 = 54\), while \((2x)^3 = (2 \cdot 3)^3 = 216\). 3. The products become \(m^3 + n^2\).

Answer

1) \((3y)^2 = 9y^2\) 2) \(54\) and \(216\) 3) \(m^3 + n^2\)
Apply properties of integer exponents 108
Lina says, “\(3x^2\) means the same thing as \(x \cdot x \cdot x + x \cdot x \cdot x\).” Check her claim. Rewrite both expressions in expanded form and in concise form, and explain her error.

Hints

- A coefficient tells how many equal terms are added. - An exponent tells how many equal factors are multiplied. - Substitute a simple value such as \(x = 2\) as a check.

Solution

1. Expand \(3x^2\) as repeated addition: \(3x^2 = x \cdot x + x \cdot x + x \cdot x\). 2. Each product in the second expression is \(x^3\), and it appears twice, so \(x \cdot x \cdot x + x \cdot x \cdot x = 2x^3\). 3. Since \(3x^2\) and \(2x^3\) are not equivalent, Lina is incorrect. She switched the roles of the coefficient and exponent.

Answer

Lina is incorrect. \(3x^2 = x \cdot x + x \cdot x + x \cdot x\), while \(x \cdot x \cdot x + x \cdot x \cdot x = 2x^3\). She confused the coefficient with the exponent.
Apply properties of integer exponents 109
Let \(T_1 = (n + 3)^2\) and \(T_2 = n^2 + 3^2\). 1) Describe in words how each expression is evaluated. 2) Evaluate both expressions for \(n = 2\) and \(n = 5\). Are the expressions equivalent? 3) A square with side length \(n\,\text{cm}\) has each side increased by \(3\,\text{cm}\). Which expression represents the area of the new square? Explain.

Hints

- Pay attention to which quantity the exponent applies to. - Equivalent expressions must have the same value for every allowable input. - The area of a square is the square of its side length.

Solution

1. For \(T_1\), add \(n\) and \(3\), then square the sum. For \(T_2\), square \(n\) and \(3\) separately, then add. 2. At \(n = 2\), \(T_1 = 25\) and \(T_2 = 13\). At \(n = 5\), \(T_1 = 64\) and \(T_2 = 34\). Since the values differ for the same inputs, the expressions are not equivalent. 3. The new side length is \(n + 3\), so the area is \((n + 3)^2\,\text{cm}^2\). Thus, \(T_1\) represents the area.

Answer

1) \(T_1\) is the square of a sum; \(T_2\) is a sum of squares. 2) For \(n = 2\): \(T_1 = 25\), \(T_2 = 13\). For \(n = 5\): \(T_1 = 64\), \(T_2 = 34\). They are not equivalent. 3) \(T_1\); the area is \((n + 3)^2\,\text{cm}^2\).
Apply properties of integer exponents 110
Evaluate each power. 1) \((-8)^2\) 2) \((-3)^3\) 3) \(\left(-\frac{2}{5}\right)^2\) 4) \((-0.1)^3\) 5) \(\left(-1\frac{1}{2}\right)^2\)

Hints

- A negative base raised to an even power gives a positive result. - A negative base raised to an odd power gives a negative result. - Convert a mixed number to an improper fraction before raising it to a power.

Solution

1. \((-8)^2 = 64\). 2. \((-3)^3 = -27\). 3. \(\left(-\frac{2}{5}\right)^2 = \frac{4}{25}\). 4. \((-0.1)^3 = -0.001\). 5. Convert the mixed number: \(-1\frac{1}{2} = -\frac{3}{2}\). Then \(\left(-\frac{3}{2}\right)^2 = \frac{9}{4} = 2\frac{1}{4}\).

Answer

1) \(64\) 2) \(-27\) 3) \(\frac{4}{25}\) 4) \(-0.001\) 5) \(2\frac{1}{4}\)
Apply properties of integer exponents 111
Let \(A = (-x)^n\) and \(B = -x^n\). a) Evaluate both expressions for \(x = 5\) and \(n = 2\). Are they equal? b) Evaluate both expressions for \(x = 5\) and \(n = 3\). What do you notice? c) For which positive integer exponents \(n\)—even or odd—is \((-x)^n = -x^n\) true for every real \(x\)? Explain.

Hints

- Identify whether the negative sign is inside or outside the base. - Track the sign of a product with an even or odd number of negative factors. - Compare the order of operations in the two expressions.

Solution

1. For \(n = 2\), \(A = (-5)^2 = 25\) and \(B = -5^2 = -25\). They are not equal. 2. For \(n = 3\), \(A = (-5)^3 = -125\) and \(B = -5^3 = -125\). They are equal. 3. When \(n\) is a positive odd integer, a product of \(n\) negative factors is negative, so \((-x)^n = -x^n\) for every real \(x\).

Answer

a) \(A = 25\), \(B = -25\); they are not equal. b) \(A = -125\), \(B = -125\); they are equal. c) The equation is true for every positive odd integer exponent \(n\).
Apply properties of integer exponents 112
Simplify each expression as one power or as the negative of one power. a) \((-a)^2 \cdot a^4\) b) \((-a)^3 \cdot a^3\) c) \(x^7 \div (-x)^4\), where \(x \ne 0\) d) \((-y)^2 \cdot (-y)^3\)

Hints

- First determine whether each power of a negative base is positive or negative. - Add exponents when multiplying powers with the same base. - Subtract exponents when dividing powers with the same nonzero base.

Solution

1. a) \((-a)^2 = a^2\), so \(a^2 \cdot a^4 = a^6\). 2. b) \((-a)^3 = -a^3\), so \(-a^3 \cdot a^3 = -a^6\). 3. c) \((-x)^4 = x^4\), so \(x^7 \div x^4 = x^3\). 4. d) Add the exponents on the common base: \((-y)^5 = -y^5\).

Answer

a) \(a^6\) b) \(-a^6\) c) \(x^3\) d) \(-y^5\)
Apply properties of integer exponents 113
Find the expression or exponent that belongs in each box. a) \(a^7 \cdot a^{\square} = a^{12}\) b) \(x^n \cdot x^4 = x^{n+\square}\) c) \(y^3 \cdot \square = -y^8\) d) \(c^{k+2} \cdot c^{k-1} = c^{\square}\)

Hints

- Add exponents for powers with the same base. - Write a simple equation for the missing exponent. - In part c), account for both the exponent and the negative sign.

Solution

1. Since \(7+\square=12\), the missing exponent is \(5\). 2. The exponent on the product is \(n+4\), so the missing exponent is \(4\). 3. The missing factor must supply a negative sign and five more factors of \(y\), so it is \(-y^5\). 4. Add the exponent expressions: \((k+2)+(k-1)=2k+1\).

Answer

a) \(5\) b) \(4\) c) \(-y^5\) d) \(2k+1\)
Apply properties of integer exponents 114
Complete each equation or expression. a) \(3x^4 \cdot \square = 12x^9\) b) \(\square \cdot (-5a^2) = 20a^3\) c) Simplify \(y^k \cdot y^5\). d) Paul says, “When multiplying powers with the same base, multiply the exponents.” Test his claim using \(2^3 \cdot 2^2\), and correct it if necessary.

Hints

- Compare the coefficients and the exponent totals separately. - For powers with the same base, examine what repeated multiplication does to the exponent count. - Test the stated rule using the numerical example before generalizing it.

Solution

1. The missing coefficient is \(12\div3=4\), and the missing exponent is \(9-4=5\), so the factor is \(4x^5\). 2. The missing coefficient is \(20\div(-5)=-4\), and the missing exponent is \(3-2=1\), so the factor is \(-4a\). 3. \(y^k\cdot y^5=y^{k+5}\). 4. \(2^3\cdot2^2=8\cdot4=32=2^5\), not \(2^6\). The exponents are added, not multiplied.

Answer

a) \(4x^5\) b) \(-4a\) c) \(y^{k+5}\) d) Paul is incorrect; \(2^3 \cdot 2^2 = 2^{3+2} = 2^5 = 32\).
Apply properties of integer exponents 115
Complete each task. 1) Simplify \(\left(-\frac{4}{7}x^5y^n\right)\left(\frac{14}{8}x^2y^3\right)\). 2) Find the missing factor: \(\square \cdot (-3a^2b^4) = 12a^5b^7\). 3) Multiply \((-u^3v^2)\) and \((1.2u^kv)\).

Hints

- Handle the numerical coefficient and each variable base separately. - For the missing factor, compare what is already present with the target product. - Keep letter-valued exponents symbolic while applying the same-base power rule.

Solution

1. The coefficient product is \(-\frac{4}{7} \cdot \frac{14}{8} = -1\). Add exponents to get \(-x^7y^{n+3}\). 2. Divide coefficients and subtract exponents: \(12 \div (-3) = -4\), \(5 - 2 = 3\), and \(7 - 4 = 3\). The factor is \(-4a^3b^3\). 3. Multiply coefficients and add exponents: \((-1) \cdot 1.2u^{3+k}v^{2+1} = -1.2u^{k+3}v^3\).

Answer

1) \(-x^7y^{n+3}\) 2) \(-4a^3b^3\) 3) \(-1.2u^{k+3}v^3\)
Apply properties of integer exponents 116
Simplify each product. a) \((7x^n)(3x^4)\) b) \((-5a^{k+2})(-2a^3)\) c) \(\left(\frac{1}{3}y^m\right)(-9y^{m-1})\)

Hints

- Multiply the coefficients. - Add exponents on common bases. - Simplify exponent expressions after adding them.

Solution

1. a) \((7 \cdot 3)x^{n+4} = 21x^{n+4}\). 2. b) \((-5 \cdot -2)a^{(k+2)+3} = 10a^{k+5}\). 3. c) \(\left(\frac{1}{3} \cdot -9\right)y^{m+(m-1)} = -3y^{2m-1}\).

Answer

a) \(21x^{n+4}\) b) \(10a^{k+5}\) c) \(-3y^{2m-1}\)
Apply properties of integer exponents 117
Find the missing factor and explain how you determined its coefficient and exponent. \((2b^n)(\square) = -10b^{n+3}\)

Hints

- Compare the coefficient of the known factor with the coefficient of the product. - Compare the exponent totals on the same base. - Substitute the completed factor to check both parts at once.

Solution

1. Divide the target coefficient by the known coefficient: \(-10 \div 2 = -5\). 2. If the missing exponent is \(r\), then \(n + r = n + 3\), so \(r = 3\). 3. The missing factor is \(-5b^3\).

Answer

\(-5b^3\)
Apply properties of integer exponents 118
Check each result. Identify correct work and correct every error. 1) \((4a^2b)(3ab^3) = 12a^2b^3\) 2) \((-5x^3y^2)(-2xy) = 10x^4y^3\) 3) \(\left(\frac{2}{3}m^2n^4\right)(6m^3n) = 4m^6n^4\)

Hints

- A variable without a written exponent has exponent \(1\). - Add exponents when multiplying powers with the same base. - Check the coefficient and each variable separately.

Solution

1. The coefficients give \(12\), but the exponents must be added: \(a^{2+1}b^{1+3} = a^3b^4\). The correct result is \(12a^3b^4\). 2. The coefficients give \(10\), and the variable powers give \(x^4y^3\). This result is correct. 3. The coefficient is \(\frac{2}{3} \cdot 6 = 4\), and the variable powers give \(m^{2+3}n^{4+1} = m^5n^5\). The correct result is \(4m^5n^5\).

Answer

1) Incorrect; \(12a^3b^4\) 2) Correct 3) Incorrect; \(4m^5n^5\)
Apply properties of integer exponents 119
A rectangular prism has edge lengths \(a = 2x^2y\), \(b = 1.5xy^2\), and \(c = 4x^3\), where \(x > 0\) and \(y > 0\). a) Write and simplify an expression for its volume \(V\). b) What is the new volume if only edge \(c\) is doubled? c) What is the new volume if all three edge lengths are doubled? State the factor by which the original volume changes.

Hints

- Use the volume formula \(V = abc\). - Group coefficients and like variable bases. - Count how many factors of \(2\) enter the volume when edges are doubled.

Solution

1. a) \(V = abc = (2x^2y)(1.5xy^2)(4x^3)\). Multiply coefficients and add exponents: \(V = 12x^6y^3\). 2. b) Doubling one edge doubles the volume, so the new volume is \(24x^6y^3\). 3. c) Doubling all three edges multiplies the volume by \(2^3 = 8\), so the new volume is \(96x^6y^3\).

Answer

a) \(12x^6y^3\) b) \(24x^6y^3\) c) \(96x^6y^3\); the volume is multiplied by \(8\).
Apply properties of integer exponents 120
Nino simplified the expressions below. Determine which results are correct. Correct each incorrect result and briefly identify the error. a) \((2z^4)^3=6z^{12}\) b) \((-5k^2)^2=25k^4\) c) \((a^3)^2=a^5\) d) \(\left(\frac{2}{3}m\right)^2=\frac{4}{9}m^2\)

Hints

- Track every factor that lies inside an outside power. - For a power raised to another power, compare a repeated-product expansion with the proposed exponent. - When a fractional coefficient is squared, check both parts of the fraction.

Solution

1. a) Incorrect. The coefficient must be cubed: \((2z^4)^3 = 2^3z^{12} = 8z^{12}\). 2. b) Correct: \((-5k^2)^2 = 25k^4\). 3. c) Incorrect. Exponents are multiplied when raising a power to a power: \((a^3)^2 = a^6\). 4. d) Correct: \(\left(\frac{2}{3}m\right)^2 = \frac{4}{9}m^2\).

Answer

a) Incorrect; \(8z^{12}\). The coefficient was multiplied by the exponent instead of raised to the power. b) Correct c) Incorrect; \(a^6\). The exponents were added instead of multiplied. d) Correct
Apply properties of integer exponents 121
Simplify each product. 1) \((1.2a^nb^k)(-5a^{n+1}b^{3k})\) 2) \(\left(-\frac{2}{5}x^{m-1}y^2\right)\left(\frac{15}{4}x^3y^{m+1}\right)\)

Hints

- Add exponents when multiplying powers with the same base. - Apply sign rules when multiplying coefficients. - Treat exponent expressions as grouped quantities before simplifying.

Solution

1. Multiply coefficients: \(1.2 \cdot (-5) = -6\). Add exponents: \(a^{n+(n+1)} = a^{2n+1}\) and \(b^{k+3k} = b^{4k}\). The result is \(-6a^{2n+1}b^{4k}\). 2. The coefficient product is \(-\frac{2}{5} \cdot \frac{15}{4} = -\frac{3}{2}\). Add exponents: \(x^{(m-1)+3} = x^{m+2}\) and \(y^{2+(m+1)} = y^{m+3}\). The result is \(-\frac{3}{2}x^{m+2}y^{m+3}\).

Answer

1) \(-6a^{2n+1}b^{4k}\) 2) \(-\frac{3}{2}x^{m+2}y^{m+3}\)
Apply properties of integer exponents 122
Find the missing coefficient \(\square\) and the value of \(n\) that make the equation true. \((4a^kb^2)(\square a^{k+1}b^n) = -12a^{2k+1}b^7\)

Hints

- Treat the coefficient and each variable base as separate matching conditions. - Check which exponent condition is already satisfied before solving for the unknown one. - Verify the completed product against every factor on the right side.

Solution

1. Compare coefficients: \(4\cdot\square=-12\), so \(\square=-3\). 2. The powers of \(a\) already match because \(a^k\cdot a^{k+1}=a^{2k+1}\). 3. Compare the powers of \(b\): \(2+n=7\), so \(n=5\).

Answer

\(\square=-3\) and \(n=5\)
Apply properties of integer exponents 123
Simplify each expression. a) \((5a^2)^3 \cdot 2a^5\) b) \((-2x^3)^4 \cdot (-3x^2)\)

Hints

- Raise each factor inside parentheses to the outside power. - Multiply exponents when raising a power to a power. - Add exponents when multiplying powers with the same base.

Solution

1. a) \((5a^2)^3 = 125a^6\). Then \(125a^6 \cdot 2a^5 = 250a^{11}\). 2. b) \((-2x^3)^4 = 16x^{12}\). Then \(16x^{12} \cdot (-3x^2) = -48x^{14}\).

Answer

a) \(250a^{11}\) b) \(-48x^{14}\)
Apply properties of integer exponents 124
Simplify \((2xy^3)^3 \cdot (-0.5x^2y)^4\).

Hints

- Simplify each powered monomial separately. - An even power makes the negative coefficient positive. - Multiply coefficients and add exponents at the end.

Solution

1. \((2xy^3)^3 = 2^3x^3y^9 = 8x^3y^9\). 2. \((-0.5x^2y)^4 = (-0.5)^4x^8y^4 = \frac{1}{16}x^8y^4\). 3. Multiply: \(8 \cdot \frac{1}{16} = \frac{1}{2}\), \(x^{3+8} = x^{11}\), and \(y^{9+4} = y^{13}\). 4. The result is \(\frac{1}{2}x^{11}y^{13}\).

Answer

\(\frac{1}{2}x^{11}y^{13}\)
Apply properties of integer exponents 125
Let \(A=(-2a^3)^4\) and \(B=(-4a^6)^2\). a) Simplify both expressions and compare their values. b) Explain without calculating why \(A\) must have a positive coefficient. c) Change only the outside exponent in \(A\) so the simplified result has a negative coefficient. Give one expression and its result.

Hints

- Apply each outside exponent to both factors inside parentheses. - Think about how an even or odd number of negative factors affects a product. - Test a different small outside exponent in part c) and check the sign.

Solution

1. \(A=(-2)^4a^{12}=16a^{12}\), and \(B=(-4)^2a^{12}=16a^{12}\). They are equivalent. 2. The even outside exponent makes the negative coefficient positive. 3. An odd outside exponent makes it negative. For example, \((-2a^3)^3=-8a^9\).

Answer

a) \(A=B=16a^{12}\) b) The outside exponent is even, so the negative coefficient \(-2\) is raised to an even power and becomes positive. c) For example, \((-2a^3)^3=-8a^9\).
Apply properties of integer exponents 126
Simplify \((-3a^kb^2)^3 \cdot (2a^2b^n)^2\).

Hints

- Simplify each powered monomial first. - Determine the sign from the parity of the outside exponent. - Add exponents when multiplying powers with the same base.

Solution

1. \((-3a^kb^2)^3 = -27a^{3k}b^6\). 2. \((2a^2b^n)^2 = 4a^4b^{2n}\). 3. Multiply the results: \((-27) \cdot 4 = -108\), \(a^{3k}a^4 = a^{3k+4}\), and \(b^6b^{2n} = b^{2n+6}\). 4. The simplified expression is \(-108a^{3k+4}b^{2n+6}\).

Answer

\(-108a^{3k+4}b^{2n+6}\)
Apply properties of integer exponents 127
Aiman claims, “It makes no difference whether I square \(-x\) and then cube the result, or cube \(-x\) and then square the result.” Test the claim by simplifying \(T_1 = ((-x)^2)^3\) and \(T_2 = ((-x)^3)^2\).

Hints

- Work from the innermost power outward. - Track the sign after an even or odd power. - Compare the final exponents and signs.

Solution

1. \(T_1 = (x^2)^3 = x^6\). 2. \(T_2 = (-x^3)^2 = x^6\). 3. Both expressions simplify to \(x^6\), so the claim is correct.

Answer

The claim is true because both expressions simplify to \(x^6\).
Apply properties of integer exponents 128
Let \(T=\frac{x^n}{y}\), where \(n\) is a positive integer, \(x\ne0\), and \(y\ne0\). a) Find \(n\) so doubling both \(x\) and \(y\) multiplies \(T\) by \(4\). b) With that value of \(n\), by what factor does \(T\) change if \(x\) is doubled and \(y\) is multiplied by \(4\)?

Hints

- Substitute the scaled variables and compare the new expression with the old one. - Use the power of a product to separate the scale factor. - For the second part, consider the numerator and denominator effects separately.

Solution

1. Doubling both variables changes the expression to \(\frac{(2x)^n}{2y}=2^{n-1}T\). 2. Since \(T\ne0\), a factor of \(4\) means \(2^{n-1}=2^2\), giving \(n=3\). 3. Doubling \(x\) now multiplies the numerator by \(2^3=8\). Multiplying \(y\) by \(4\) divides the ratio by \(4\). 4. The net factor is \(\frac{8}{4}=2\).

Answer

a) \(n=3\) b) The value of \(T\) is multiplied by \(2\).
Apply properties of integer exponents 129
Evaluate each expression, paying close attention to signs. 1) \((-4)^2\) and \(-4^2\) 2) \((-1)^{101}\) and \((-1)^{202}\) 3) \((-2)^5 + (-3)^3\) 4) \(-(-1)^{2n}\) for any natural number \(n\)

Hints

- Determine whether the negative sign is inside the base. - Use even and odd exponents to determine signs. - Evaluate powers before addition or subtraction.

Solution

1. \((-4)^2 = 16\), while \(-4^2 = -16\). 2. Since \(101\) is odd, \((-1)^{101} = -1\). Since \(202\) is even, \((-1)^{202} = 1\). 3. \((-2)^5 + (-3)^3 = -32 - 27 = -59\). 4. Since \(2n\) is even, \((-1)^{2n} = 1\), so \(-(-1)^{2n} = -1\).

Answer

1) \(16\) and \(-16\) 2) \(-1\) and \(1\) 3) \(-59\) 4) \(-1\)
Apply properties of integer exponents 130
Evaluate each expression. 1) \(\left(-\frac{2}{3}\right)^3\) 2) \(0.2^2 - (-0.1)^3\) 3) \((-1)^7 \cdot \left(\frac{1}{2}\right)^2 + 0.75\) 4) Evaluate \(T(x, y) = x^4 - y^3\) for \(x = -2\) and \(y = -2\).

Hints

- Apply powers before multiplication, addition, or subtraction. - Raise both numerator and denominator of a fraction to the power. - Use parentheses when substituting negative values.

Solution

1. \(\left(-\frac{2}{3}\right)^3 = -\frac{8}{27}\). 2. \(0.2^2 - (-0.1)^3 = 0.04 - (-0.001) = 0.041\). 3. \((-1)^7 \cdot \left(\frac{1}{2}\right)^2 + 0.75 = -0.25 + 0.75 = 0.5\). 4. \((-2)^4 - (-2)^3 = 16 - (-8) = 24\).

Answer

1) \(-\frac{8}{27}\) 2) \(0.041\) 3) \(0.5\) 4) \(24\)
Apply properties of integer exponents 131
Simplify each expression as much as possible using properties of exponents. Assume \(k, n, p\) are positive integers and all variable values make the expressions defined. 1. \((-3a^2b^k)^4\) 2. \(\left(\frac{2x^n}{y^3}\right)^3\) 3. \(\frac{(m^4q^2)^p}{m^{3p}}\)

Hints

- What happens to the exponents when a power is raised to another power? - How does an even outer exponent affect a negative factor? - When dividing powers with the same base, subtract the exponents. - Apply the outer exponent to every factor inside the parentheses.

Solution

1. Apply the exponent to every factor: \((-3a^2b^k)^4 = (-3)^4(a^2)^4(b^k)^4 = 81a^8b^{4k}\). 2. Raise the numerator and denominator to the third power: \(\left(\frac{2x^n}{y^3}\right)^3 = \frac{2^3(x^n)^3}{(y^3)^3} = \frac{8x^{3n}}{y^9}\). 3. Simplify the numerator, then divide powers with the same base: \(\frac{(m^4q^2)^p}{m^{3p}} = \frac{m^{4p}q^{2p}}{m^{3p}} = m^{4p-3p}q^{2p} = m^pq^{2p}\).

Answer

1. \(81a^8b^{4k}\) 2. \(\frac{8x^{3n}}{y^9}\) 3. \(m^pq^{2p}\)
Apply properties of integer exponents 132
For \(a\ne0\), \(b\ne0\), and \(c\ne0\), simplify \(\frac{a^3b^{-2}c^4}{a^{-1}b^2c}\cdot\frac{b^4}{a^2c^3}\). Show that the final result depends only on \(a\).

Hints

- Simplify the first quotient one variable at a time. - Rewrite factors in the second fraction with exponent notation before multiplying. - Check which variables have a total exponent of \(0\).

Solution

1. Simplify the first fraction by subtracting exponents: \(a^{3-(-1)}b^{-2-2}c^{4-1}=a^4b^{-4}c^3\). 2. Multiply by the second fraction: \(a^4b^{-4}c^3\cdot b^4a^{-2}c^{-3}\). 3. Combine exponents: \(a^{4-2}b^{-4+4}c^{3-3}=a^2b^0c^0=a^2\). 4. Since the exponents of \(b\) and \(c\) are \(0\), those factors equal \(1\), so the result depends only on \(a\).

Answer

\(a^2\). The factors involving \(b\) and \(c\) cancel.
Apply properties of integer exponents 133
Simplify the expression as much as possible for \(x, y, z \ne 0\): \(\frac{(4x^3y)^2(3z^2)^3}{12x^4(yz)^2}\)

Hints

- Simplify the powers in the numerator and denominator separately. - Apply the outer exponent to every factor in a product. - When dividing powers with the same base, subtract the exponents. - Treat the numerical coefficients and variable factors separately.

Solution

1. Expand the powers in the numerator: \((4x^3y)^2 = 16x^6y^2\) and \((3z^2)^3 = 27z^6\). 2. Multiply the numerator: \(16 \cdot 27x^6y^2z^6 = 432x^6y^2z^6\). 3. Expand the denominator: \(12x^4(yz)^2 = 12x^4y^2z^2\). 4. Divide coefficients and subtract exponents of like bases: \(\frac{432}{12}x^{6-4}y^{2-2}z^{6-2} = 36x^2z^4\).

Answer

\(36x^2z^4\)
Apply properties of integer exponents 134
For \(a \ne 0\), let \(A = \frac{[(-a)^2(-2a)^2]^2}{(-2a^2)^3}\). a) Simplify \(A\) as much as possible. b) Evaluate the expression when \(a = -2\).

Hints

- Simplify the numerator and denominator separately before dividing. - When dividing powers with the same base, subtract the exponents. - Use parentheses when substituting a negative number for \(a\).

Solution

1. Simplify inside the brackets in the numerator: \((-a)^2 = a^2\) and \((-2a)^2 = 4a^2\), so their product is \(4a^4\). 2. Square the product: \((4a^4)^2 = 16a^8\). 3. Simplify the denominator: \((-2a^2)^3 = (-2)^3(a^2)^3 = -8a^6\). 4. Divide: \(\frac{16a^8}{-8a^6} = -2a^{8-6} = -2a^2\). 5. Substitute \(a = -2\): \(-2(-2)^2 = -2 \cdot 4 = -8\).

Answer

a) \(-2a^2\) b) \(-8\)
Apply properties of integer exponents 135
Simplify the expression as much as possible. Assume \(m\) and \(n\) are positive integers and \(a, b \ne 0\): \(\frac{(2a^n b^{2m})^5}{8a^{3n}(b^m)^{10}}\)

Hints

- Apply an exponent outside parentheses to every factor inside. - Use the power of a power property. - When dividing powers with the same base, subtract the exponents. - Recall the value of a nonzero base raised to the zero power.

Solution

1. Apply the exponent to each factor in the numerator: \((2a^n b^{2m})^5 = 2^5(a^n)^5(b^{2m})^5 = 32a^{5n}b^{10m}\). 2. Simplify the power in the denominator: \((b^m)^{10} = b^{10m}\). 3. Divide: \(\frac{32a^{5n}b^{10m}}{8a^{3n}b^{10m}} = 4a^{5n-3n}b^{10m-10m}\). 4. Since \(b^0 = 1\), the expression simplifies to \(4a^{2n}\).

Answer

\(4a^{2n}\)
Apply properties of integer exponents 136
Simplify using exponent properties. Assume \(k\) and \(n\) are positive integers, \(x+y\ne0\), and \(z\ne0\): \(\frac{[5(x+y)^{2k}z^n]^2}{25(x+y)^{3k}z^{2n}}\cdot\frac{1}{(x+y)^k}\). Explain why the final value does not depend on \(x\), \(y\), or \(z\).

Hints

- Apply the outside exponent to the coefficient and both variable factors. - Treat \(x+y\) as one base. - Simplify the quotient before multiplying by the final reciprocal.

Solution

1. Expand the powered numerator: \([5(x+y)^{2k}z^n]^2=25(x+y)^{4k}z^{2n}\). 2. Divide by the denominator: \(\frac{25(x+y)^{4k}z^{2n}}{25(x+y)^{3k}z^{2n}}=(x+y)^k\). 3. Multiply by the last factor: \((x+y)^k\cdot\frac{1}{(x+y)^k}=1\). 4. Every variable factor cancels, so the final value is independent of \(x\), \(y\), and \(z\).

Answer

\(1\). All variable factors cancel.
Apply properties of integer exponents 137
Evaluate each expression. Give each answer as an integer or a fraction in lowest terms. a) \(6^{-2}\) b) \(\left(\frac{2}{3}\right)^{-3}\) c) \((-0.2)^{-2}\) d) \(-4^{-2}\) e) \(24\cdot2^{-4}\)

Hints

- A negative exponent means take the reciprocal. - Notice whether a negative sign belongs to the base or stands outside the power. - Rewrite decimals as fractions when useful.

Solution

1. \(6^{-2}=\frac{1}{6^2}=\frac{1}{36}\). 2. \(\left(\frac{2}{3}\right)^{-3}=\left(\frac{3}{2}\right)^3=\frac{27}{8}\). 3. \((-0.2)^{-2}=\left(-\frac{1}{5}\right)^{-2}=(-5)^2=25\). 4. In \(-4^{-2}\), the negative sign is outside the power, so the value is \(-\frac{1}{16}\). 5. \(24\cdot2^{-4}=24\cdot\frac{1}{16}=\frac{3}{2}\).

Answer

a) \(\frac{1}{36}\) b) \(\frac{27}{8}\) c) \(25\) d) \(-\frac{1}{16}\) e) \(\frac{3}{2}\)
Apply properties of integer exponents 138
Rewrite each expression without a fraction bar by using negative exponents. Preserve the grouping. 1) \(\frac{a^3b^2}{c^4}\), where \(c\ne0\) 2) \(\frac{1}{x^2+y^2}\), where \(x^2+y^2\ne0\) 3) \(\frac{1}{r^3}-\frac{1}{s^3}\cdot\frac{1}{t^2}\), where \(r,s,t\ne0\) 4) \(\frac{1}{u^2v^3}\), where \(u\ne0\) and \(v\ne0\)

Hints

- Treat a sum or difference in a denominator as one grouped base. - Change the sign of an exponent when moving a factor across the fraction bar. - Preserve multiplication before subtraction in part 3).

Solution

1. Move \(c^4\) to the numerator with exponent \(-4\): \(a^3b^2c^{-4}\). 2. Treat the entire sum as one base: \((x^2+y^2)^{-1}\). 3. Rewrite each reciprocal while preserving the order of operations: \(r^{-3}-s^{-3}t^{-2}\). 4. Move both denominator factors to the numerator: \(u^{-2}v^{-3}\).

Answer

1) \(a^3b^2c^{-4}\) 2) \((x^2+y^2)^{-1}\) 3) \(r^{-3}-s^{-3}t^{-2}\) 4) \(u^{-2}v^{-3}\)
Apply properties of integer exponents 139
Rewrite each rational expression as a product with no fraction bar. Use negative exponents as needed. 1) \(\frac{7x^2}{y^3}\), where \(y\ne0\) 2) \(\frac{a^4}{5b^{-2}}\), where \(b\ne0\) 3) \(\frac{u^{-1}v^2}{w^3z^{-4}}\), where \(u,w,z\ne0\) 4) \(\frac{1}{8p^2q^{-3}}\), where \(p\ne0\) and \(q\ne0\)

Hints

- Move denominator factors to the numerator by changing exponent signs. - Handle numerical coefficients separately. - A negative exponent in the denominator becomes positive in the numerator.

Solution

1. \(\frac{7x^2}{y^3}=7x^2y^{-3}\). 2. Move \(b^{-2}\) to the numerator and invert the coefficient: \(\frac{a^4}{5b^{-2}}=0.2a^4b^2\). 3. Move the denominator factors to the numerator: \(u^{-1}v^2w^{-3}z^4\). 4. Invert the coefficient and denominator powers: \(0.125p^{-2}q^3\).

Answer

1) \(7x^2y^{-3}\) 2) \(0.2a^4b^2\) 3) \(u^{-1}v^2w^{-3}z^4\) 4) \(0.125p^{-2}q^3\)
Apply properties of integer exponents 140
Assume every variable appearing in a denominator or with a negative exponent is nonzero. Simplify each expression and write the result as a product with no fraction bar. 1) \(\frac{4x^5}{2x^7y^2}\) 2) \(\frac{(2a)^{-2}b^3}{a^2c}\) 3) \(\frac{0.25u^2v^{-1}}{w^2z^{-2}}\)

Hints

- Simplify coefficients before removing the fraction bar. - Apply a negative exponent to every factor inside parentheses. - Change exponent signs when moving denominator factors.

Solution

1. Divide coefficients and subtract exponents: \(2x^{-2}y^{-2}\). 2. Since \((2a)^{-2}=0.25a^{-2}\), dividing by \(a^2c\) gives \(0.25a^{-4}b^3c^{-1}\). 3. Move the denominator factors to the numerator: \(0.25u^2v^{-1}w^{-2}z^2\).

Answer

1) \(2x^{-2}y^{-2}\) 2) \(0.25a^{-4}b^3c^{-1}\) 3) \(0.25u^2v^{-1}w^{-2}z^2\)
Apply properties of integer exponents 141
Rewrite each rational expression with no fraction bar. Use negative exponents as needed. Assume \(m\) and \(n\) are integers. 1) \(\frac{1}{y^{m+3}}\), where \(y\ne0\) 2) \(\frac{15a^4}{5^{-1}b^{-n}c^2}\), where \(b\ne0\) and \(c\ne0\)

Hints

- Negate the entire exponent expression when moving a power from the denominator. - Treat coefficients and variable factors separately. - Distribute the leading negative sign across \(m+3\).

Solution

1. Move the denominator power to the numerator: \(y^{-(m+3)}=y^{-m-3}\). 2. Moving the denominator factors changes their exponent signs: \(15a^4\cdot5^1b^nc^{-2}\). 3. Multiply the coefficients: \(15\cdot5=75\), so the result is \(75a^4b^nc^{-2}\).

Answer

1) \(y^{-m-3}\) 2) \(75a^4b^nc^{-2}\)
Apply properties of integer exponents 142
Let \(T_1=\frac{2}{(x+y)^{-3}}\) and \(T_2=\frac{1}{0.5(x+y)^{-3}}\). Determine whether the expressions are equivalent for all \(x\ne-y\). Justify your answer by rewriting both without fraction bars.

Hints

- Move the negative power from the denominator to the numerator. - Find the reciprocal of \(0.5\). - Compare the two rewritten expressions.

Solution

1. Move \((x+y)^{-3}\) from the denominator: \(T_1=2(x+y)^3\). 2. Since the reciprocal of \(0.5\) is \(2\), \(T_2=2(x+y)^3\). 3. Both expressions simplify to the same result, so they are equivalent for every allowed pair.

Answer

Yes. Both expressions simplify to \(2(x+y)^3\) for \(x\ne-y\).
Apply properties of integer exponents 143
Rewrite each expression with no fraction bar. Use negative-exponent properties and simplify as far as possible. Assume \(x+y\ne0\), \(a-b\ne0\), \(p\ne0\), and \(m-n\ne0\). 1) \(\frac{12}{(x+y)^{-2}}\) 2) \(\frac{5ab}{2(a-b)^{-3}}\) 3) \(\frac{3^{-1}(m+n)}{6^{-1}p^{-2}(m-n)^{-1}}\)

Hints

- Change the sign of a denominator exponent when moving the factor to the numerator. - Simplify numerical coefficients separately. - Keep each binomial in parentheses and treat it as one base.

Solution

1. Move \((x+y)^{-2}\) from the denominator: \(12(x+y)^2\). 2. Since \(5\div2=2.5\), moving \((a-b)^{-3}\) gives \(2.5ab(a-b)^3\). 3. The coefficient is \(3^{-1}\div6^{-1}=\frac13\div\frac16=2\). Move the remaining negative-power factors from the denominator to obtain \(2p^2(m+n)(m-n)\).

Answer

1) \(12(x+y)^2\) 2) \(2.5ab(a-b)^3\) 3) \(2p^2(m+n)(m-n)\)
Apply properties of integer exponents 144
Let \(T=\frac{0.2(a+b)}{5^{-1}c^{-2}(a-b)^{-2}}\), where \(c\ne0\) and \(a\ne b\). a) Simplify \(T\) without a fraction bar. b) Evaluate it when \(a=7\), \(b=3\), and \(c=0.1\).

Hints

- Compare the decimal coefficient with the power of five. - Interpret each negative exponent as a reciprocal. - Simplify before substituting the given values.

Solution

1. Since \(5^{-1}=0.2\), the numerical factors cancel. 2. Moving the negative powers out of the denominator gives \(T=c^2(a+b)(a-b)^2\). 3. Substitute: \(T=(0.1)^2(7+3)(7-3)^2=0.01\cdot10\cdot16=1.6\).

Answer

a) \(T=c^2(a+b)(a-b)^2\) b) \(1.6\)
Apply properties of integer exponents 145
Assume \(x\ne0\) and \(y\ne0\). Two students simplify \(S=\frac{2^{-3}x^2y^{-2}}{8^{-1}x^{-1}y}\). Leon claims the result is \(x^3y^{-3}\). Sophie claims the result is \(\frac{x^3}{y^3}\). Check both claims and determine whether the results are equivalent.

Hints

- Simplify the numerical coefficient first. - Subtract exponents for each variable separately. - Rewrite the negative exponent as a reciprocal to compare the answers.

Solution

1. The numerical quotient is \(2^{-3}\div8^{-1}=\frac{1}{8}\div\frac{1}{8}=1\). 2. For \(x\), \(x^2\div x^{-1}=x^{2-(-1)}=x^3\). 3. For \(y\), \(y^{-2}\div y=y^{-3}\). 4. Thus \(S=x^3y^{-3}\), so Leon is correct. 5. Since \(y^{-3}=\frac{1}{y^3}\), \(x^3y^{-3}=\frac{x^3}{y^3}\), so Sophie is also correct.

Answer

Both students are correct because \(x^3y^{-3}=\frac{x^3}{y^3}\).
Apply properties of integer exponents 146
Use exponent properties to simplify. In both parts, let \(k,n\in\mathbb{Z}\), and assume all expressions are defined. a) \(\frac{15a^{2k}b^{k-1}}{3a^kb^{2k}}\) b) \(\left(\frac{1}{2}x^{-n}y^2\right)^{-2}\cdot4x^{-2n}\)

Hints

- Treat variable expressions in exponents like numerical expressions. - Apply an outside exponent to every factor. - Subtract negative exponents carefully.

Solution

1. Divide coefficients and subtract exponents: \(5a^{2k-k}b^{(k-1)-2k}=5a^kb^{-k-1}=\frac{5a^k}{b^{k+1}}\). 2. Expand the power: \(\left(\frac{1}{2}x^{-n}y^2\right)^{-2}=4x^{2n}y^{-4}\). Multiplying by \(4x^{-2n}\) gives \(16x^0y^{-4}=\frac{16}{y^4}\).

Answer

a) \(\frac{5a^k}{b^{k+1}}\) b) \(\frac{16}{y^4}\)
Apply properties of integer exponents 147
Assume \(x\ne0,-2\). a) Show that \(\frac{1}{4x^2}\) and \(0.25x^{-2}\) are equivalent. b) Rewrite \(T=\frac{3}{5(x+2)^2}\) with no fraction bar. c) Evaluate \(T\) when \(x=3\).

Hints

- Separate the numerical coefficient from the variable power. - Treat the entire binomial \(x+2\) as the base. - Evaluate the parentheses before applying the negative exponent.

Solution

1. For a), \(\frac{1}{4x^2}=\frac{1}{4}\cdot\frac{1}{x^2}=0.25x^{-2}\). 2. For b), \(\frac{3}{5}=0.6\), so \(T=0.6(x+2)^{-2}\). 3. For c), \(T=0.6(3+2)^{-2}=0.6\cdot5^{-2}=0.6\cdot0.04=0.024\).

Answer

a) \(\frac{1}{4x^2}=0.25x^{-2}\) b) \(0.6(x+2)^{-2}\) c) \(0.024\)
Apply properties of integer exponents 148
Rewrite each expression using only positive exponents. Simplify as far as possible. 1) \(\frac{6a^{-3}}{b^{-2}}\) 2) \(\frac{(x+y)^{-1}}{2^{-3}z^{-4}}\) 3) \(\frac{p^{-2}q^3}{r^{-1}(p-q)^{-2}}\)

Hints

- Move a negative power across the fraction bar to make its exponent positive. - Treat a binomial in parentheses as one base. - Preserve all restrictions from the original expression.

Solution

1. Move the negative powers across the fraction bar: \(\frac{6b^2}{a^3}\). 2. Move \(2^{-3}\) and \(z^{-4}\) to the numerator: \(\frac{2^3z^4}{x+y}=\frac{8z^4}{x+y}\). 3. Move the negative powers: \(\frac{q^3r(p-q)^2}{p^2}\). 4. The original restrictions are \(a,b\ne0\); \(x+y\ne0\) and \(z\ne0\); and \(p\ne0\), \(r\ne0\), and \(p-q\ne0\).

Answer

1) \(\frac{6b^2}{a^3}\), where \(a,b\ne0\) 2) \(\frac{8z^4}{x+y}\), where \(x+y\ne0\) and \(z\ne0\) 3) \(\frac{q^3r(p-q)^2}{p^2}\), where \(p\ne0\), \(r\ne0\), and \(p\ne q\)
Apply properties of integer exponents 149
Two expressions are equivalent if they have the same value for every allowed input. Determine whether \(A=\frac{(2x)^{-3}}{y^{-2}}\) and \(B=\frac{y^2}{8x^3}\) are equivalent for \(x\ne0\) and \(y\ne0\). Justify your answer by rewriting \(A\).

Hints

- Rewrite the numerator and denominator without negative exponents. - Apply the exponent to both factors in \(2x\). - Divide by multiplying by the reciprocal.

Solution

1. Rewrite the numerator: \((2x)^{-3}=\frac{1}{(2x)^3}=\frac{1}{8x^3}\). 2. Rewrite the denominator: \(y^{-2}=\frac{1}{y^2}\). 3. Simplify the complex fraction: \(A=\frac{1}{8x^3}\div\frac{1}{y^2}=\frac{1}{8x^3}\cdot y^2=\frac{y^2}{8x^3}\). 4. This is exactly \(B\), so the expressions are equivalent.

Answer

Yes. Both expressions equal \(\frac{y^2}{8x^3}\) for \(x\ne0\) and \(y\ne0\).
Apply properties of integer exponents 150
Simplify each expression using exponent properties. Assume \(x\ne0\), \(m\ne0\), and \(n\ne0\). a) \(\frac{(2x^2)(x^{-2})}{x^{-3}}\) b) \(\frac{(3m^2n^{-1})^2}{9m^{-1}n}\) Write each result with positive exponents only.

Hints

- Handle the numerical coefficient and each letter base separately. - Multiplying like bases and dividing like bases change exponents in different ways. - In part b), apply the outside power before the quotient rule.

Solution

1. In a), the coefficient remains \(2\), and the exponent of \(x\) is \(2+(-2)-(-3)=3\). The result is \(2x^3\). 2. In b), the numerator is \(9m^4n^{-2}\). 3. Divide each like base: \(\frac{9m^4n^{-2}}{9m^{-1}n}=m^{4-(-1)}n^{-2-1}=m^5n^{-3}=\frac{m^5}{n^3}\).

Answer

a) \(2x^3\) b) \(\frac{m^5}{n^3}\)
Apply properties of integer exponents 151
Two students simplify \((y^{-2})^3\), where \(y\ne0\). Talia gets \(y^{-6}\). Micah gets \(y^{-5}\). Who is correct? Show why the correct expression works for every nonzero \(y\), not just one value. Rewrite it without negative exponents, then check using \(y=2\).

Hints

- How would you write the outside cube as a product of equal factors? - Use the exponent rule on that product before testing a particular value. - Does checking one value prove two expressions always agree?

Solution

1. For any \(y\ne0\), \((y^{-2})^3=y^{-2}\cdot y^{-2}\cdot y^{-2}=y^{-6}\). Talia is correct because there are three factors with exponent \(-2\). 2. Rewrite \(y^{-6}=\frac{1}{y^6}\). 3. At \(y=2\), both \((2^{-2})^3\) and \(\frac{1}{2^6}\) equal \(\frac{1}{64}\). Checking one input alone would not prove equivalence.

Answer

Talia is correct for all \(y\ne0\): \((y^{-2})^3=y^{-2}\cdot y^{-2}\cdot y^{-2}=y^{-6}=\frac{1}{y^6}\). At \(y=2\), both forms equal \(\frac{1}{64}\).
Apply properties of integer exponents 152
Simplify. Assume all expressions are defined. a) \((-x^{-4})^{-2}\) b) \(\frac{(-1)^{k+2}}{(-1)^k}\), where \(k\in\mathbb{Z}\) c) \(\left(\frac{2a^2}{3b^{-1}}\right)^{-3}\)

Hints

- Apply an outside exponent to every factor. - Subtract exponents when dividing like bases. - A negative exponent takes the reciprocal.

Solution

1. \((-x^{-4})^{-2}=(-1)^{-2}x^8=x^8\). 2. \(\frac{(-1)^{k+2}}{(-1)^k}=(-1)^2=1\). 3. First, \(\frac{2a^2}{3b^{-1}}=\frac{2a^2b}{3}\). Taking the reciprocal and cubing gives \(\left(\frac{3}{2a^2b}\right)^3=\frac{27}{8a^6b^3}\).

Answer

a) \(x^8\) b) \(1\) c) \(\frac{27}{8a^6b^3}\)
Apply properties of integer exponents 153
Simplify using exponent properties. Assume \(a\ne0\), \(x\ne0\), \(y\ne0\), and \(n\in\mathbb{Z}\). a) \(\frac{(-a)^3\cdot a^{-5}}{a^{-2}}\) b) \(\left[\left(-\frac{x}{y}\right)^{-n}\right]^2\) c) \(\frac{5^{2n+1}}{25^n}\)

Hints

- Determine the sign of a negative base with an odd or even exponent. - Multiply exponents for a power of a power. - Rewrite \(25\) using base \(5\).

Solution

1. Since \((-a)^3=-a^3\), the quotient is \(-a^{3-5-(-2)}=-a^0=-1\). 2. The power of a power gives \(\left(-\frac{x}{y}\right)^{-2n}\). Since \(-2n\) is even, this equals \(\left(\frac{x}{y}\right)^{-2n}=\frac{y^{2n}}{x^{2n}}\). 3. Rewrite \(25^n=(5^2)^n=5^{2n}\). Then \(\frac{5^{2n+1}}{5^{2n}}=5\).

Answer

a) \(-1\) b) \(\frac{y^{2n}}{x^{2n}}\) c) \(5\)
Apply properties of integer exponents 154
Assume \(a\ne0\), \(b\ne0\), and \(x\ne0\). Use integer-exponent properties. 1) Simplify \((b^{-4}b^3)^{-1}\). 2) Simplify \(\frac{(15x^2)(5x^0)}{5x^{-2}}\). 3) Rewrite \(\frac{(a^2b^{-1})^{-2}}{a^{-3}b}\) with positive exponents. 4) Find the integer \(n\) such that \(\frac{2a^n b^{-2}}{a^{-2}b^3}=\frac{2a^5}{b^5}\) for every nonzero \(a\) and \(b\).

Hints

- Work from the innermost powers outward. - Keep coefficients and like letter bases separate. - Replace negative exponents with reciprocals only after simplifying. - For an identity with an unknown exponent, match the power of the same base on both sides.

Solution

1. Inside the parentheses, \(b^{-4}b^3=b^{-1}\). Raising this to \(-1\) gives \(b\). 2. Since \(x^0=1\), the coefficient is \(\frac{15\cdot5}{5}=15\), and the exponent is \(2+0-(-2)=4\). The result is \(15x^4\). 3. The numerator becomes \(a^{-4}b^2\). Dividing gives \(a^{-4-(-3)}b^{2-1}=a^{-1}b=\frac{b}{a}\). 4. The left side is \(2a^{n+2}b^{-5}\). To match \(2a^5b^{-5}\) for every nonzero input, \(n+2=5\), so \(n=3\).

Answer

1) \(b\) 2) \(15x^4\) 3) \(\frac{b}{a}\) 4) \(n=3\)
Apply properties of integer exponents 155
For \(a+b\ne0\) and \(a-b\ne0\), simplify \(B=\frac{(a+b)^{-2}}{(a-b)^{-2}}\). Then evaluate the result for \(a=5\) and \(b=3\).

Hints

- Treat each binomial as one base. - Rewrite both negative exponents as reciprocals. - Dividing by a fraction means multiplying by its reciprocal.

Solution

1. Rewrite the negative powers: \((a+b)^{-2}=\frac{1}{(a+b)^2}\) and \((a-b)^{-2}=\frac{1}{(a-b)^2}\). 2. Divide by multiplying by the reciprocal: \(B=\frac{1}{(a+b)^2}\cdot(a-b)^2=\frac{(a-b)^2}{(a+b)^2}\). 3. For \(a=5\) and \(b=3\), \(B=\frac{(5-3)^2}{(5+3)^2}=\frac{4}{64}=\frac{1}{16}\).

Answer

The simplified expression is \(\frac{(a-b)^2}{(a+b)^2}\). For \(a=5\) and \(b=3\), the value is \(\frac{1}{16}\).
Apply properties of integer exponents 156
Let \(x\ne0\) and \(y\ne0\). a) Rewrite \((xy)^{-1}\) as a product of powers of \(x\) and \(y\). Explain why the two forms are equivalent. b) Evaluate both forms when \(x=2\) and \(y=5\). c) Maja claims that \((x+y)^{-1}=x^{-1}+y^{-1}\). Use \(x=2\) and \(y=5\) to determine whether the claim is true.

Hints

- Interpret an exponent of \(-1\) using reciprocals. - Compare the product forms after expressing each negative power as a fraction. - In part c), evaluate the two sides independently rather than assuming a power distributes over addition.

Solution

1. By the definition of a negative exponent, \((xy)^{-1}=\frac{1}{xy}\). 2. Also, \(x^{-1}y^{-1}=\frac{1}{x}\cdot\frac{1}{y}=\frac{1}{xy}\). Therefore, \((xy)^{-1}=x^{-1}y^{-1}\). 3. When \(x=2\) and \(y=5\), both forms equal \(\frac{1}{10}=0.1\). 4. For Maja's claim, \((2+5)^{-1}=\frac{1}{7}\), while \(2^{-1}+5^{-1}=\frac{1}{2}+\frac{1}{5}=\frac{7}{10}\). The values are different, so the claim is false.

Answer

a) \((xy)^{-1}=x^{-1}y^{-1}\) b) Both forms equal \(\frac{1}{10}=0.1\). c) The claim is false: \((2+5)^{-1}=\frac{1}{7}\), but \(2^{-1}+5^{-1}=\frac{7}{10}\).
Apply properties of integer exponents 157
For positive integer \(n\) and nonzero \(a\) and \(b\), simplify without negative exponents: \(T=\left(\frac{a^n}{b^n}\right)^{-2}\). Then evaluate the result for \(a=2\), \(b=4\), and \(n=2\).

Hints

- A negative exponent on a fraction takes the reciprocal. - Apply the outside exponent to both numerator and denominator. - Simplify the quotient of the substituted values before evaluating the power.

Solution

1. A negative exponent reverses the fraction: \(T=\left(\frac{b^n}{a^n}\right)^2\). 2. Apply the outside exponent: \(T=\frac{b^{2n}}{a^{2n}}=\left(\frac{b}{a}\right)^{2n}\). 3. For \(a=2\), \(b=4\), and \(n=2\), \(T=\left(\frac42\right)^4=2^4=16\).

Answer

\(T=\frac{b^{2n}}{a^{2n}}\). The numerical value is \(16\).
Apply properties of integer exponents 158
Let \(T=\frac{4a^n b^{-3}}{2a^2b^m}\), where \(a\ne0\) and \(b\ne0\). Find the integer values of \(n\) and \(m\) that make the simplified expression \(2a^3b^{-5}\). Justify your answer using exponent rules.

Hints

- Simplify the coefficient and each variable base separately. - Use the quotient rule to write an equation for each exponent. - Match the resulting exponents to those in the target expression.

Solution

1. Simplify the numerical coefficient: \(4\div2=2\). 2. For base \(a\), the quotient rule gives \(a^n\div a^2=a^{n-2}\). Set \(n-2=3\), so \(n=5\). 3. For base \(b\), the quotient rule gives \(b^{-3}\div b^m=b^{-3-m}\). Set \(-3-m=-5\), so \(m=2\). 4. With \(n=5\) and \(m=2\), the expression simplifies to \(2a^3b^{-5}\).

Answer

\(n=5\) and \(m=2\)
Apply properties of integer exponents 159
Find \(z\) so that each equation is true. a) \(5^z\cdot\frac{1}{125}=5^{-1}\) b) \((x^{-2})^z x^5=x^{-1}\) for every \(x>0\) with \(x\ne1\) c) \(\left(\frac{2}{3}\right)^z=\frac{9}{4}\)

Hints

- Rewrite each numerical fraction as a power with the same base as the other side. - For a product of powers, combine the exponents before matching them. - A reciprocal reverses the base and changes the sign of the exponent.

Solution

1. For a), write \(\frac{1}{125}=5^{-3}\). Then \(z-3=-1\), so \(z=2\). 2. For b), \((x^{-2})^z x^5=x^{-2z+5}\). Set \(-2z+5=-1\), so \(z=3\). 3. For c), \(\frac{9}{4}=\left(\frac{3}{2}\right)^2=\left(\frac{2}{3}\right)^{-2}\). Therefore, \(z=-2\).

Answer

a) \(z=2\) b) \(z=3\) c) \(z=-2\)
Apply properties of integer exponents 160
Simplify completely without negative exponents. Assume \(p\ne0\), \(q\ne0\), \(x\ne0\), \(a\ne0\), and \(b\ne0\). a) \(\frac{(3p^{-2}q)^2}{9p^{-4}q^3}\) b) \(\frac{(-x^2)^{-3}\cdot x^8}{x^{-2}}\) c) \(\left(\frac{2a^{-3}}{b^2}\right)^{-2}\cdot\frac{a^{-6}}{b^4}\)

Hints

- Expand powers of products and quotients first. - Track the sign when a negative base has an odd exponent. - Look for factors that cancel after exponent properties are applied.

Solution

1. The numerator in part a is \(9p^{-4}q^2\). Dividing gives \(p^0q^{-1}=\frac{1}{q}\). 2. \((-x^2)^{-3}=-x^{-6}\). Then \(\frac{-x^{-6}\cdot x^8}{x^{-2}}=-x^{2-(-2)}=-x^4\). 3. \(\left(\frac{2a^{-3}}{b^2}\right)^{-2}=\frac{a^6b^4}{4}\). Multiplying by \(\frac{a^{-6}}{b^4}\) gives \(\frac{1}{4}\).

Answer

a) \(\frac{1}{q}\) b) \(-x^4\) c) \(\frac{1}{4}\)
Apply properties of integer exponents 161
Let \(n\) be an integer and let \(y\) be a nonzero real number. Consider \(T=\frac{(y^n)^2}{y^4\cdot y^2}\). a) Simplify \(T\) to a single power of \(y\) whose exponent depends on \(n\). b) For what value of \(n\) is \(T=1\) for every nonzero real value of \(y\)? Justify your answer using exponent properties. c) Find the value of \(T\) when \(n=4\) and \(y=3\).

Hints

- Simplify the numerator and denominator separately using exponent properties. - A nonzero base raised to the zero power equals \(1\). - Substitute into the simplified expression for part c.

Solution

1. Use the power-of-a-power property: \((y^n)^2=y^{2n}\). Combine the denominator: \(y^4\cdot y^2=y^6\). Therefore, \(T=\frac{y^{2n}}{y^6}=y^{2n-6}\). 2. For \(T\) to equal \(1\) for every nonzero \(y\), the exponent must be \(0\). Solve \(2n-6=0\) to get \(n=3\). 3. When \(n=4\), \(T=y^{2(4)-6}=y^2\). For \(y=3\), \(T=3^2=9\).

Answer

a) \(y^{2n-6}\) b) \(n=3\) c) \(9\)
Apply properties of integer exponents 162
Complete the following tasks about properties of exponents. 1. Find an expression \(T\) such that \(T^3 = -8x^6y^{3n}\). 2. Use algebraic steps to determine whether the equation below is true for all \(a, b \ne 0\) and nonnegative integers \(n\) and \(m\): \(\frac{(a^n b)^m}{a^{nm}} = b^m\) 3. Consider \((-x^2)^k\). For which positive integers \(k\) does \((-x^2)^k = x^{2k}\) hold for all real \(x\)? Briefly justify your answer.

Hints

- For part 1, consider the numerical coefficient and each variable factor separately. - For part 2, apply the power of a product and power of a power properties before canceling common factors. - For part 3, test how the sign changes for a few even and odd values of \(k\).

Solution

1. Find a factor whose cube gives each part of the expression: \((-2)^3 = -8\), \((x^2)^3 = x^6\), and \((y^n)^3 = y^{3n}\). Therefore, \(T = -2x^2y^n\). 2. Simplify the left side: \(\frac{(a^n b)^m}{a^{nm}} = \frac{(a^n)^m b^m}{a^{nm}} = \frac{a^{nm}b^m}{a^{nm}} = b^m\). The equation is true under the stated conditions. 3. \((-x^2)^k = (-1)^k(x^2)^k = (-1)^kx^{2k}\). If \(k\) is even, then \((-1)^k = 1\), so the identity holds for every real \(x\). If \(k\) is odd, it fails for every \(x \ne 0\). Therefore, it holds for all real \(x\) exactly when \(k\) is even.

Answer

1. \(T = -2x^2y^n\) 2. The equation is true because the left side simplifies to \(b^m\). 3. The identity holds for all real \(x\) exactly when \(k\) is even.
Apply properties of integer exponents 163
Simplify using exponent properties. Write the answer without negative exponents. Assume \(x\ne0\), \(y\ne0\), and \(z\ne0\). \(\frac{(x^2y^{-3})^2\cdot(x^4z^2)^3}{(x^2yz)^4}\cdot\frac{y^2}{z^{-1}}\)

Hints

- Expand every power of a product first. - Subtract exponents when dividing like bases. - Move factors with negative exponents across the fraction bar.

Solution

1. Expand the powers: \((x^2y^{-3})^2=x^4y^{-6}\), \((x^4z^2)^3=x^{12}z^6\), and \((x^2yz)^4=x^8y^4z^4\). 2. The first fraction simplifies to \(x^{16-8}y^{-6-4}z^{6-4}=x^8y^{-10}z^2\). 3. Since \(\frac{y^2}{z^{-1}}=y^2z\), the full product is \(x^8y^{-8}z^3=\frac{x^8z^3}{y^8}\).

Answer

\(\frac{x^8z^3}{y^8}\)
Apply properties of integer exponents 164
For \(a\ne0\), \(b\ne0\), and \(c\ne0\), simplify and write the result as a product of powers: \(\frac{(5a^2b^{-1})^2\cdot(2a^{-2}c)^3}{(10a^{-1}b^{-2}c^2)^2}\).

Hints

- Expand each power of a product first. - Combine the numerator before dividing. - Subtract negative exponents carefully.

Solution

1. Expand the numerator: \((5a^2b^{-1})^2=25a^4b^{-2}\) and \((2a^{-2}c)^3=8a^{-6}c^3\). Their product is \(200a^{-2}b^{-2}c^3\). 2. Expand the denominator: \((10a^{-1}b^{-2}c^2)^2=100a^{-2}b^{-4}c^4\). 3. Divide coefficients and subtract exponents: \(2a^0b^2c^{-1}=2b^2c^{-1}\).

Answer

\(2b^2c^{-1}\)
Apply properties of integer exponents 165
Simplify the expression as much as possible using properties of exponents: \([(-2x)^2]^3 - (-4x^3)^2 + [-(2x)^3]^2 - 2(-2x^2)^3\)

Hints

- Track the sign carefully when a negative base is raised to an even or odd power. - Simplify the innermost powers first. - Use \((a^m)^n = a^{mn}\). - After simplifying, check whether all terms contain the same power of \(x\).

Solution

1. Simplify the first term: \([(-2x)^2]^3 = (4x^2)^3 = 64x^6\). 2. Simplify the second term: \((-4x^3)^2 = 16x^6\). 3. Simplify the third term: \([-(2x)^3]^2 = (-8x^3)^2 = 64x^6\). 4. Simplify the factor in the fourth term: \(2(-2x^2)^3 = 2(-8x^6) = -16x^6\). 5. Combine like terms, including the subtraction before the fourth term: \(64x^6 - 16x^6 + 64x^6 - (-16x^6) = 128x^6\).

Answer

\(128x^6\)
Apply properties of integer exponents 166
Evaluate using exponent properties. a) \((1.5)^{-2}+\left(\frac{1}{3}\right)^{-1}\cdot4^{-1}\) b) \(\frac{3^{-1}+\left(\frac{2}{3}\right)^{-2}}{2^2-7\cdot2^{-1}}\)

Hints

- Rewrite decimals as fractions. - Evaluate the numerator and denominator separately. - Dividing by a fraction means multiplying by its reciprocal.

Solution

1. For part a, \((1.5)^{-2}=\left(\frac{3}{2}\right)^{-2}=\frac{4}{9}\), \(\left(\frac{1}{3}\right)^{-1}=3\), and \(4^{-1}=\frac{1}{4}\). Thus \(\frac{4}{9}+\frac{3}{4}=\frac{43}{36}\). 2. For part b, the numerator is \(\frac{1}{3}+\frac{9}{4}=\frac{31}{12}\). The denominator is \(4-\frac{7}{2}=\frac{1}{2}\). Therefore, \(\frac{31}{12}\div\frac{1}{2}=\frac{31}{6}\).

Answer

a) \(\frac{43}{36}\) b) \(\frac{31}{6}\)
Apply properties of integer exponents 167
Evaluate and give the result as a fraction in lowest terms or as a decimal: \(\frac{2^3\cdot2^{-5}+3^{-2}}{\left(\frac{1}{3}\right)^2-(-2)^{-2}}\).

Hints

- Combine powers with the same base first. - Evaluate the main numerator and denominator separately. - Track the sign of the denominator carefully.

Solution

1. The numerator is \(2^{-2}+\frac{1}{9}=\frac{1}{4}+\frac{1}{9}=\frac{13}{36}\). 2. The denominator is \(\frac{1}{9}-\frac{1}{4}=-\frac{5}{36}\). 3. Divide: \(\frac{13}{36}\div\left(-\frac{5}{36}\right)=-\frac{13}{5}=-2.6\).

Answer

\(-\frac{13}{5}\), or \(-2.6\)

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