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Meaning of rational exponents

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5148939
Rewrite each equation in the other form. Change power notation to radical notation, or radical notation to power notation. Example: \(5^3=125\Rightarrow\sqrt[3]{125}=5\) a) \(13^2=169\) b) \(\sqrt[3]{216}=6\) c) \(0.2^5=0.00032\) d) \(\sqrt[4]{\frac{16}{81}}=\frac{2}{3}\)

Hints

- Identify the base, exponent, and result. - The power exponent becomes the radical index. - A square-root index of \(2\) is usually omitted.

Solution

1. \(13^2=169\) becomes \(\sqrt{169}=13\). 2. \(\sqrt[3]{216}=6\) becomes \(6^3=216\). 3. \(0.2^5=0.00032\) becomes \(\sqrt[5]{0.00032}=0.2\). 4. \(\sqrt[4]{\frac{16}{81}}=\frac{2}{3}\) becomes \(\left(\frac{2}{3}\right)^4=\frac{16}{81}\).

Answer

a) \(\sqrt{169}=13\) b) \(6^3=216\) c) \(\sqrt[5]{0.00032}=0.2\) d) \(\left(\frac{2}{3}\right)^4=\frac{16}{81}\)
5101619
Use \(\sqrt{10^{2n}}=10^n\), valid for \(n\in\mathbb{Z}\), to evaluate each square root without a calculator. First rewrite each radicand as a power of \(10\). a) \(\sqrt{100{,}000{,}000}\) b) \(\sqrt{0.000001}\) c) \(\sqrt{\frac{10^3}{10^7}}\)

Hints

- Rewrite every radicand as a power of \(10\). - Numbers between \(0\) and \(1\) use negative powers of \(10\). - Subtract exponents before taking the square root in part c.

Solution

1. The identity follows from \(\sqrt{10^{2n}}=(10^{2n})^{\frac{1}{2}}=10^n\). 2. \(100{,}000{,}000=10^8\), so \(\sqrt{10^8}=10^4=10{,}000\). 3. \(0.000001=10^{-6}\), so \(\sqrt{10^{-6}}=10^{-3}=0.001\). 4. \(\frac{10^3}{10^7}=10^{-4}\), so \(\sqrt{10^{-4}}=10^{-2}=0.01\).

Answer

a) \(10{,}000\) b) \(0.001\) c) \(0.01\)
5101629
Use exponent properties to justify \(\sqrt{5^{2k}}=5^k\) for \(k\in\mathbb{Z}\). Then evaluate exactly: \(\sqrt{5^6}\), \(\sqrt{5^{-4}}\), and \(\sqrt{\frac{1}{5^2}}\).

Hints

- Prove the general identity before evaluating the examples. - A negative exponent creates a reciprocal. - Rewrite the last radicand as a power of \(5\).

Solution

1. Rewrite the square root as a rational exponent: \(\sqrt{5^{2k}}=(5^{2k})^{\frac{1}{2}}=5^k\). 2. \(\sqrt{5^6}=5^3=125\). 3. \(\sqrt{5^{-4}}=5^{-2}=\frac{1}{25}\). 4. \(\sqrt{\frac{1}{5^2}}=\sqrt{5^{-2}}=5^{-1}=\frac{1}{5}\).

Answer

\(\sqrt{5^{2k}}=(5^{2k})^{\frac{1}{2}}=5^k\) \(\sqrt{5^6}=125\) \(\sqrt{5^{-4}}=\frac{1}{25}\) \(\sqrt{\frac{1}{5^2}}=\frac{1}{5}\)
5143269
Evaluate each expression without a calculator. Write each result as a natural number or a decimal. a) \(\sqrt{5^4}\) b) \(\sqrt{2^{10}}\) c) \(\sqrt{10^{-6}}\) d) \(\sqrt{0.49\cdot10^8}\)

Hints

- Rewrite a square root as a power with exponent \(\frac{1}{2}\). - Use the power-of-a-power property. - Recognize \(0.49\) as a perfect-square decimal. - Apply the product property when a product appears under the radical.

Solution

1. \(\sqrt{5^4}=5^{4/2}=5^2=25\). 2. \(\sqrt{2^{10}}=2^{10/2}=2^5=32\). 3. \(\sqrt{10^{-6}}=10^{-3}=0.001\). 4. \(\sqrt{0.49\cdot10^8}=\sqrt{0.49}\cdot\sqrt{10^8}=0.7\cdot10^4=7000\).

Answer

a) \(25\) b) \(32\) c) \(0.001\) d) \(7000\)
5148949
Evaluate each expression without a calculator using rational exponents. a) \(27^{\frac43}\) b) \(\sqrt[3]{10^9}\) c) \(0.09^{1.5}\) d) \(\sqrt[4]{0.0016}\)

Hints

- Rewrite decimal exponents as fractions. - Take the root before the remaining power when convenient. - Look for familiar perfect powers.

Solution

1. \(27^{\frac43}=(\sqrt[3]{27})^4=3^4=81\). 2. \(\sqrt[3]{10^9}=(10^9)^{\frac13}=10^3=1000\). 3. \(0.09^{1.5}=0.09^{\frac32}=(\sqrt{0.09})^3=(0.3)^3=0.027\). 4. \(\sqrt[4]{0.0016}=0.0016^{\frac14}=0.2\), since \((0.2)^4=0.0016\).

Answer

a) \(81\) b) \(1000\) c) \(0.027\) d) \(0.2\)
5148969
Solve each power equation over the real numbers. State the number of solutions. a) \(x^2=144\) b) \(x^3=-125\) c) \(x^4=0\) d) \(x^6=-64\)

Hints

- First identify whether the exponent is even or odd. - Taking an \(n\)th root corresponds to using an exponent of \(\frac{1}{n}\). - Consider the sign of the number on the right side. - An even power can never be negative over the real numbers.

Solution

1. For \(x^2=144\), take both square roots: \(x=\pm\sqrt{144}=\pm144^{1/2}=\pm12\). There are two solutions. 2. For \(x^3=-125\), take the cube root: \(x=\sqrt[3]{-125}=-5\). There is one real solution. 3. For \(x^4=0\), the only solution is \(x=0\). 4. For \(x^6=-64\), no real solution exists because an even power cannot be negative.

Answer

a) \(\{-12,12\}\); two solutions b) \(\{-5\}\); one solution c) \(\{0\}\); one solution d) \(\varnothing\); no real solution
5148999
Order the expressions from least to greatest. Evaluate them without a calculator. \(a=\sqrt[4]{81}\) \(b=32^{0.4}\) \(c=\sqrt{2}\cdot\sqrt{18}\) \(d=16^{0.25}\) \(e=\sqrt[7]{0}\)

Hints

- Convert decimal exponents to fractions. - Use \(x^{\frac{m}{n}}=\sqrt[n]{x^m}\). - Combine square roots in a product when possible.

Solution

1. \(e=0\). 2. Since \(0.25=\frac{1}{4}\), \(d=\sqrt[4]{16}=2\). 3. \(a=\sqrt[4]{81}=3\). 4. Since \(0.4=\frac{2}{5}\), \(b=32^{\frac{2}{5}}=(\sqrt[5]{32})^2=4\). 5. \(c=\sqrt{2\cdot18}=\sqrt{36}=6\). 6. Therefore, \(0<2<3<4<6\), so the order is \(e,d,a,b,c\).

Answer

\(e<d<a<b<c\), with values \(0<2<3<4<6\)
5149029
Find all real solutions. Give exact answers and decimal approximations rounded to two decimal places when appropriate. If no real solution exists, briefly explain why. a) \(x^4=150\) b) \(x^3=-200\) c) \(x^6=-10\) d) \(x^5=32\)

Hints

- Determine the number of real solutions from the exponent's parity and the right side's sign. - An \(n\)th root can be written using an exponent of \(\frac{1}{n}\). - Include both signs for an even power with a positive result. - Round only after finding the exact form.

Solution

1. Since \(x^4=150\) has a positive right side and an even exponent, \(x=\pm150^{1/4}=\pm\sqrt[4]{150}\approx\pm3.50\). 2. Since the exponent is odd, \(x^3=-200\) has one real solution: \(x=-200^{1/3}=-\sqrt[3]{200}\approx-5.85\). 3. The equation \(x^6=-10\) has no real solution because an even power is never negative. 4. \(x^5=32\) has the exact solution \(x=32^{1/5}=\sqrt[5]{32}=2\).

Answer

a) \(x=\pm150^{1/4}=\pm\sqrt[4]{150}\approx\pm3.50\) b) \(x=-200^{1/3}=-\sqrt[3]{200}\approx-5.85\) c) No real solution d) \(x=32^{1/5}=2\)
5149059
Determine whether each statement is true or false without a calculator. Justify each answer by raising the proposed value to the corresponding power or by using sign reasoning. 1. \(\sqrt[3]{-0.125}=-0.5\) 2. \(\sqrt{0.0064}=0.08\) 3. \(\sqrt[4]{625}=25\) 4. \(\sqrt{(-9)^2}=-9\) 5. \(\sqrt[5]{-32}=-2\)

Hints

- Check a proposed radical value by raising it to the radical index. - Odd powers preserve the sign of a negative base. - A principal even root is never negative.

Solution

1. True, because \((-0.5)^3=-0.125\). 2. True, because \((0.08)^2=0.0064\). 3. False, because \(5^4=625\), so \(\sqrt[4]{625}=5\). 4. False, because a principal square root is nonnegative: \(\sqrt{(-9)^2}=\sqrt{81}=9\). 5. True, because \((-2)^5=-32\).

Answer

Statements 1, 2, and 5 are true. Statements 3 and 4 are false.
5149079
Order the expressions from least to greatest. \(a=\sqrt[3]{-8}\) \(b=\sqrt{0.25}\) \(c=-\sqrt[4]{81}\) \(d=\sqrt{(-3)^2}\) \(e=\sqrt[5]{32}\)

Hints

- Evaluate each expression first. - Notice whether a negative sign is inside or outside a radical. - A principal square root is nonnegative.

Solution

1. \(a=-2\). 2. \(b=0.5\). 3. \(c=-3\). 4. \(d=3\), because a principal square root is nonnegative. 5. \(e=2\). 6. Therefore, \(-3<-2<0.5<2<3\), so \(c<a<b<e<d\).

Answer

\(c<a<b<e<d\)
5149089
Find the real solution set for each equation without using a calculator. a) \(x^4=625\) b) \(x^3=-64\) c) \(x^8=1\) d) \(x^5=0\)

Hints

- Decide whether each exponent is even or odd. - An even power with a positive result can have two real bases. - An odd power has exactly one real base. - Use familiar integer powers to evaluate the roots.

Solution

1. Since \(5^4=625\) and the exponent is even, \(x=\pm5\). 2. Since \((-4)^3=-64\), \(x=-4\). 3. Both \(1^8=1\) and \((-1)^8=1\), so \(x=\pm1\). 4. The only number whose fifth power is \(0\) is \(0\), so \(x=0\).

Answer

a) \(\{-5,5\}\) b) \(\{-4\}\) c) \(\{-1,1\}\) d) \(\{0\}\)
5149239
Evaluate without a calculator. a) \(\sqrt[3]{216}\) b) \(\sqrt[4]{0.0625}\) c) \(\sqrt[5]{32^{-1}}\) d) \(\sqrt[3]{\frac{27}{1000}}\)

Hints

- Rewrite each radicand as a familiar power. - For fractions, take the root of the numerator and denominator. - A negative exponent represents a reciprocal.

Solution

1. Since \(6^3=216\), \(\sqrt[3]{216}=6\). 2. Since \((0.5)^4=0.0625\), \(\sqrt[4]{0.0625}=0.5\). 3. Since \(32^{-1}=2^{-5}=(0.5)^5\), \(\sqrt[5]{32^{-1}}=0.5\). 4. \(\sqrt[3]{\frac{27}{1000}}=\frac{3}{10}=0.3\).

Answer

a) \(6\) b) \(0.5\) c) \(0.5\) d) \(0.3\)
5149419
Rewrite each expression in radical form, then evaluate it without a calculator. a) \(144^{0.5}\) b) \(\left(\frac1{27}\right)^{-\frac13}\) c) \(32^{0.4}\) d) \(1000^{-\frac23}\)

Hints

- Convert decimal exponents to fractions. - A negative exponent takes the reciprocal. - Evaluate the root before the remaining power when convenient.

Solution

1. \(144^{0.5}=144^{\frac12}=\sqrt{144}=12\). 2. \(\left(\frac1{27}\right)^{-\frac13}=27^{\frac13}=\sqrt[3]{27}=3\). 3. \(32^{0.4}=32^{\frac25}=(\sqrt[5]{32})^2=4\). 4. \(1000^{-\frac23}=\frac1{(\sqrt[3]{1000})^2}=\frac1{100}=0.01\).

Answer

a) \(12\) b) \(3\) c) \(4\) d) \(0.01\)
5149449
Write each expression in radical form. Reduce the exponent first when possible. Assume \(x>0\), \(y>0\), \(z>0\), and \(a>0\). a) \(x^{\frac23}\) b) \(y^{1.5}\) c) \(z^{-\frac12}\) d) \((4a)^{\frac34}\)

Hints

- Convert decimal exponents to fractions. - A negative exponent places the positive power in the denominator. - The denominator of a rational exponent gives the radical index.

Solution

1. \(x^{\frac23}=\sqrt[3]{x^2}\). 2. Since \(1.5=\frac32\), \(y^{1.5}=\sqrt{y^3}\). 3. \(z^{-\frac12}=\frac1{\sqrt z}\). 4. \((4a)^{\frac34}=\sqrt[4]{(4a)^3}=\sqrt[4]{64a^3}\).

Answer

a) \(\sqrt[3]{x^2}\) b) \(\sqrt{y^3}\) c) \(\frac1{\sqrt z}\) d) \(\sqrt[4]{64a^3}\)
5149459
Two students discuss \(\sqrt[6]{64}\). Lucas says, “It is exactly the same as \(\sqrt[3]{8}\).” Maya says, “The result can also be written as \(2^1\).” Rewrite every expression in the form \(2^n\). Who is correct?

Hints

- Write \(64\) and \(8\) as powers of \(2\). - Rewrite each radical as a rational exponent. - Compare the resulting powers of \(2\).

Solution

1. \(\sqrt[6]{64}=\sqrt[6]{2^6}=2^1\). 2. \(\sqrt[3]{8}=\sqrt[3]{2^3}=2^1\). 3. Both statements are correct because all three expressions equal \(2\).

Answer

Both students are correct: \(\sqrt[6]{64}=\sqrt[3]{8}=2^1=2\).
5149479
Rewrite each expression as a rational exponent, reduce the exponent, and then return to radical form. Assume \(b>0\), \(z>0\), and \(y>0\). a) \(\sqrt[12]{b^3}\) b) \(\sqrt[10]{z^{15}}\) c) \(\frac1{\sqrt[6]{y^4}}\)

Hints

- Write each radical as an exponent fraction. - Reduce the fraction just as you would any other fraction. - A negative exponent creates a reciprocal.

Solution

1. \(\sqrt[12]{b^3}=b^{\frac3{12}}=b^{\frac14}=\sqrt[4]{b}\). 2. \(\sqrt[10]{z^{15}}=z^{\frac{15}{10}}=z^{\frac32}=\sqrt{z^3}\). 3. \(\frac1{\sqrt[6]{y^4}}=y^{-\frac46}=y^{-\frac23}=\frac1{\sqrt[3]{y^2}}\).

Answer

a) \(\sqrt[4]{b}\) b) \(\sqrt{z^3}\) c) \(\frac1{\sqrt[3]{y^2}}\)
5149509
Rewrite each radical expression as a rational exponent and evaluate it. Round to three decimal places when necessary. a) \(\sqrt[4]{20}\) b) \(\sqrt[3]{5^2}\) c) \(\frac1{\sqrt[5]{10}}\) d) \(\sqrt[3]{-27}\)

Hints

- The radical index becomes the denominator of the exponent. - A reciprocal produces a negative exponent. - Odd roots of negative numbers are real.

Solution

1. \(\sqrt[4]{20}=20^{\frac14}\approx2.115\). 2. \(\sqrt[3]{5^2}=5^{\frac23}\approx2.924\). 3. \(\frac1{\sqrt[5]{10}}=10^{-\frac15}\approx0.631\). 4. \(\sqrt[3]{-27}=(-27)^{\frac13}=-3\).

Answer

a) \(20^{\frac14}\approx2.115\) b) \(5^{\frac23}\approx2.924\) c) \(10^{-\frac15}\approx0.631\) d) \(-3\)
5149539
Find the natural-number value of each expression and identify which expressions are equal. \(A=16^{\frac34}\) \(B=\sqrt[3]{8^2}\) \(C=\left(\frac14\right)^{-1.5}\) \(D=\sqrt{2^6}\)

Hints

- Rewrite every base as a power of \(2\). - Convert the decimal exponent to a fraction. - Apply the power-of-a-power property.

Solution

1. \(A=(2^4)^{\frac34}=2^3=8\). 2. \(B=\sqrt[3]{2^6}=2^2=4\). 3. \(C=\left(\frac14\right)^{-\frac32}=4^{\frac32}=8\). 4. \(D=(2^6)^{\frac12}=2^3=8\). 5. Therefore \(A=C=D\), while \(B=4\).

Answer

\(A=8\), \(B=4\), \(C=8\), and \(D=8\). Thus \(A=C=D\).
5149569
The four expressions below have the same value. Show this algebraically by rewriting each expression as a power of \(5\). \(T_1=\sqrt[4]{5^6}\) \(T_2=\sqrt{5^3}\) \(T_3=25^{\frac34}\) \(T_4=125^{\frac12}\)

Hints

- Rewrite each radical using a rational exponent. - Express \(25\) and \(125\) as powers of \(5\). - Apply the power-of-a-power property.

Solution

1. \(T_1=\sqrt[4]{5^6}=5^{\frac64}=5^{\frac32}\). 2. \(T_2=\sqrt{5^3}=5^{\frac32}\). 3. Since \(25=5^2\), \(T_3=(5^2)^{\frac34}=5^{\frac64}=5^{\frac32}\). 4. Since \(125=5^3\), \(T_4=(5^3)^{\frac12}=5^{\frac32}\). 5. All four expressions equal \(5^{\frac32}\), so they have the same value.

Answer

\(T_1=T_2=T_3=T_4=5^{\frac32}\).
5149599
Simplify each expression completely and write the result without a radical. Assume all variables are positive and \(k\) is a natural number with \(k\ge2\). a) \(\sqrt[3]{x^9}\) b) \(\sqrt[5]{a^{10}b^{20}}\) c) \(\frac1{\sqrt[4]{y^{12}}}\) d) \(\sqrt[k]{z^{5k}}\)

Hints

- Rewrite an \(n\)th root as an exponent of \(\frac1n\). - Apply the exponent to each factor in a product. - A factor moved from the denominator to the numerator has the opposite exponent. - Reduce each exponent fraction.

Solution

1. \(\sqrt[3]{x^9}=x^{\frac93}=x^3\). 2. \(\sqrt[5]{a^{10}b^{20}}=a^{\frac{10}{5}}b^{\frac{20}{5}}=a^2b^4\). 3. \(\frac1{\sqrt[4]{y^{12}}}=\frac1{y^{\frac{12}{4}}}=y^{-3}\). 4. \(\sqrt[k]{z^{5k}}=z^{\frac{5k}{k}}=z^5\).

Answer

a) \(x^3\) b) \(a^2b^4\) c) \(y^{-3}\) d) \(z^5\)
5149629
Use exponent properties to simplify each expression completely. Assume all variables are positive real numbers. a) \(3^{\frac14}\cdot3^{\frac34}\) b) \(x^{\frac56}\div x^{\frac13}\) c) \((4y)^{\frac12}\cdot y^{\frac12}\) d) \(\sqrt[5]{a^2}\cdot\sqrt[5]{a^3}\)

Hints

- Add exponents when multiplying powers with the same base. - Subtract exponents when dividing powers with the same base. - Distribute an exponent over a product. - Rewrite each radical as a rational exponent.

Solution

1. \(3^{\frac14}\cdot3^{\frac34}=3^{\frac14+\frac34}=3\). 2. \(x^{\frac56}\div x^{\frac13}=x^{\frac56-\frac26}=x^{\frac12}\). 3. \((4y)^{\frac12}\cdot y^{\frac12}=4^{\frac12}y^{\frac12}y^{\frac12}=2y\). 4. \(\sqrt[5]{a^2}\cdot\sqrt[5]{a^3}=a^{\frac25}a^{\frac35}=a\).

Answer

a) \(3\) b) \(x^{\frac12}\) c) \(2y\) d) \(a\)
5149659
Determine whether the two expressions in each pair are equivalent. Rewrite the radicals as rational exponents and simplify to justify your conclusion. a) \(A=\sqrt[3]{27^2}\) and \(B=(\sqrt[3]{27})^2\) b) \(C=\sqrt[4]{x^{12}}\) and \(D=x^2\sqrt{x^2}\), where \(x>0\)

Hints

- Rewrite an \(n\)th root as a power with exponent \(\frac1n\). - Apply the power-of-a-power property. - Express \(27\) as a power of \(3\). - Multiply powers with the same base by adding exponents.

Solution

1. \(A=(27^2)^{\frac13}=27^{\frac23}=(3^3)^{\frac23}=3^2=9\). 2. \(B=(27^{\frac13})^2=27^{\frac23}=9\). Therefore \(A\) and \(B\) are equivalent. 3. \(C=(x^{12})^{\frac14}=x^3\). 4. Since \(x>0\), \(D=x^2(x^2)^{\frac12}=x^2\cdot x=x^3\). Therefore \(C\) and \(D\) are equivalent.

Answer

a) Yes. Both expressions equal \(9\). b) Yes. Both expressions simplify to \(x^3\).
5149749
Simplify each expression completely. Assume all variables are positive real numbers. a) \(\sqrt[3]{x^2}\sqrt[6]{x^2}\) b) \(\frac{\sqrt{a^5}}{\sqrt[4]{a^2}}\) c) \((\sqrt b+\sqrt a)(\sqrt b-\sqrt a)\)

Hints

- Rewrite radicals as powers with rational exponents. - Add or subtract exponents when the bases are the same. - Reduce exponent fractions before combining them. - Use the difference-of-squares pattern in part c).

Solution

1. \(\sqrt[3]{x^2}\sqrt[6]{x^2}=x^{\frac23}x^{\frac26}=x^{\frac23+\frac13}=x\). 2. \(\frac{\sqrt{a^5}}{\sqrt[4]{a^2}}=a^{\frac52-\frac24}=a^{\frac52-\frac12}=a^2\). 3. Apply the difference-of-squares pattern: \((\sqrt b+\sqrt a)(\sqrt b-\sqrt a)=(\sqrt b)^2-(\sqrt a)^2=b-a\).

Answer

a) \(x\) b) \(a^2\) c) \(b-a\)
5149779
For \(x>0\), simplify the expression and write the result without a radical: \(x^{-\frac12}\sqrt[4]{x^6}\)

Hints

- Rewrite the fourth root as a rational exponent. - Add exponents when multiplying powers with the same base. - Reduce the resulting exponent.

Solution

1. Rewrite the radical: \(\sqrt[4]{x^6}=x^{\frac64}=x^{\frac32}\). 2. Multiply powers with the same base by adding exponents: \(x^{-\frac12}x^{\frac32}=x^{-\frac12+\frac32}=x^1=x\).

Answer

\(x\)
5149829
A metal cube has surface area \(S=54\,\text{cm}^2\). Use the formula \(V=\left(\frac S6\right)^{1.5}\) to find its volume. Show how rational exponents are used.

Hints

- Substitute the surface area and simplify inside the parentheses. - Rewrite \(1.5\) as a fraction. - An exponent of \(\frac12\) represents a square root.

Solution

1. Substitute \(S=54\): \(V=\left(\frac{54}{6}\right)^{1.5}=9^{1.5}\). 2. Rewrite the decimal exponent: \(1.5=\frac32\), so \(V=9^{\frac32}\). 3. Evaluate using the square root first: \(9^{\frac32}=(\sqrt9)^3=3^3=27\). 4. The volume is \(27\,\text{cm}^3\).

Answer

\(27\,\text{cm}^3\)
5154099
Evaluate: \(\sqrt{1.44}+\sqrt[3]{0.008}-\sqrt[4]{0.0001}\).

Hints

- Rewrite each decimal as a familiar power. - Check how decimal places change when a decimal is squared, cubed, or raised to the fourth power.

Solution

1. \(\sqrt{1.44}=1.2\). 2. \(\sqrt[3]{0.008}=0.2\). 3. \(\sqrt[4]{0.0001}=0.1\). 4. Therefore, \(1.2+0.2-0.1=1.3\).

Answer

\(1.3\)
5154189
For \(a>0\), simplify the expression and write the result as a single power of \(a\): \(\frac{a^{\frac56}\sqrt[3]{a}}{a^{-\frac12}}\)

Hints

- Rewrite the cube root as a rational exponent. - Add exponents in the numerator. - Subtract the denominator exponent, including its negative sign. - Use a common denominator for the exponent fractions.

Solution

1. Rewrite the radical: \(\sqrt[3]{a}=a^{\frac13}\). 2. Combine the numerator powers: \(a^{\frac56}a^{\frac13}=a^{\frac56+\frac26}=a^{\frac76}\). 3. Divide by subtracting exponents: \(a^{\frac76-(-\frac12)}=a^{\frac76+\frac36}=a^{\frac{10}{6}}=a^{\frac53}\).

Answer

\(a^{\frac53}\)
5154299
Consider the equation \(2(x^n-4)=120\). Find all real solutions for each value of \(n\), and briefly explain why the number of solutions differs. a) \(n=3\) b) \(n=6\)

Hints

- Rewrite the equation in the form \(x^n=c\) before substituting values for \(n\). - Use a rational exponent to undo each power, then account for whether the exponent is odd or even. - Compare what happens when a positive value is raised to an odd power and to an even power.

Solution

1. First rewrite the equation: \(2(x^n-4)=120\), so \(x^n-4=60\) and \(x^n=64\). 2. For \(n=3\), \(x^3=64\), so \(x=64^{1/3}=4\). An odd power gives one real solution. 3. For \(n=6\), \(x^6=64\), so \(x=\pm64^{1/6}=\pm2\). An even power equal to a positive number gives two real solutions.

Answer

a) \(x=4\) b) \(x=\pm2\) The odd exponent gives one real solution, while the even exponent gives two real solutions because the right side is positive.
5154309
Let \(f(x)=\frac{1}{2}x^n\). a) The point \(P(4,32)\) lies on the graph. Find the nonnegative integer exponent \(n\). b) Using the exponent from part a, find the input \(a\) for which \(f(a)=4\).

Hints

- Substitute the point into the function rule. - Isolate the exponential expression before identifying the exponent. - A cube root can be written using an exponent of \(\frac{1}{3}\).

Solution

1. Substitute \((4,32)\): \(32=\frac{1}{2}4^n\). 2. Multiply by \(2\): \(64=4^n\). Since \(4^3=64\), \(n=3\). 3. Use \(n=3\): \(\frac{1}{2}a^3=4\). 4. Multiply by \(2\): \(a^3=8\), so \(a=8^{1/3}=\sqrt[3]{8}=2\).

Answer

a) \(n=3\) b) \(a=8^{1/3}=2\)
5246259
Evaluate each expression, then order the results from least to greatest. a) \(\sqrt[3]{-0.125}\) b) \(\sqrt[5]{243}\) c) \(\sqrt[3]{-\frac{27}{64}}\) d) \(\sqrt[4]{0.0001}\)

Hints

- Rewrite each radicand as a familiar power. - Odd roots of negative numbers are negative. - Convert fractions to decimals only if it helps compare the values.

Solution

1. \(\sqrt[3]{-0.125}=-0.5\). 2. \(\sqrt[5]{243}=3\). 3. \(\sqrt[3]{-\frac{27}{64}}=-\frac{3}{4}=-0.75\). 4. \(\sqrt[4]{0.0001}=0.1\). 5. Therefore, \(-0.75<-0.5<0.1<3\), so the order is \(c<a<d<b\).

Answer

a) \(-0.5\) b) \(3\) c) \(-0.75\) d) \(0.1\) Order: \(c<a<d<b\)
5246379
Evaluate without a calculator. 1) \(\sqrt[3]{0.001}\) 2) \(16^{\frac{3}{4}}\) 3) \(\sqrt{\frac{25}{144}}\) 4) \(\sqrt[4]{625}\)

Hints

- Rewrite each radicand as a familiar power. - Interpret a rational exponent as a root followed by a power. - Take the square root of a fraction by taking the square root of its numerator and denominator.

Solution

1. Since \((0.1)^3=0.001\), the value is \(0.1\). 2. \(16^{\frac{3}{4}}=(\sqrt[4]{16})^3=2^3=8\). 3. \(\sqrt{\frac{25}{144}}=\frac{5}{12}\). 4. Since \(5^4=625\), the value is \(5\).

Answer

1) \(0.1\) 2) \(8\) 3) \(\frac{5}{12}\) 4) \(5\)
5246389
Determine whether each statement is true or false. Correct each false statement. a) \(\sqrt[3]{8}\cdot\sqrt[3]{27}=\sqrt[3]{216}\) b) \(100^{\frac{1}{2}}-64^{\frac{1}{3}}=2\) c) \(\sqrt{\sqrt{16}}=2\) d) \(\sqrt[4]{0.0001}=0.01\)

Hints

- Evaluate each root or rational exponent separately. - Check a proposed root by raising it to the radical index. - For a nested square root, work from the inside out.

Solution

a) True. \(\sqrt[3]{8}\cdot\sqrt[3]{27}=2\cdot3=6\), and \(\sqrt[3]{216}=6\). b) False. \(100^{\frac{1}{2}}-64^{\frac{1}{3}}=10-4=6\). c) True. \(\sqrt{\sqrt{16}}=\sqrt{4}=2\). d) False. Since \((0.1)^4=0.0001\), \(\sqrt[4]{0.0001}=0.1\).

Answer

a) True b) False; the correct value is \(6\). c) True d) False; the correct value is \(0.1\).
5246419
A cube-shaped water tank holds \(216\,\text{L}\). Use \(1\,\text{L}=1\,\text{dm}^3\). a) Find the edge length of the tank in decimeters. b) A larger cube-shaped tank holds \(1728\,\text{L}\). Find its edge length. c) Compare the edge lengths and the volumes of the two tanks.

Hints

- Use a \(1/3\) power, equivalently a cube root, to find an edge length from a volume. - The volume of a cube with edge length \(s\) is \(s^3\). - Compare how multiplying an edge length affects the volume.

Solution

1. For the first tank, \(s^3=216\), so \(s=216^{1/3}=\sqrt[3]{216}=6\,\text{dm}\). 2. For the larger tank, \(s^3=1728\), so \(s=1728^{1/3}=\sqrt[3]{1728}=12\,\text{dm}\). 3. The edge-length ratio is \(12:6=2:1\). The volume ratio is \(1728:216=8:1\), which agrees with \(2^3=8\).

Answer

a) \(6\,\text{dm}\) b) \(12\,\text{dm}\) c) The larger tank has twice the edge length and eight times the volume.
5246519
Which expressions have real values? Justify each answer. 1) \(\sqrt[4]{-81}\) 2) \(\sqrt[5]{-32}\) 3) \(\sqrt[6]{(-2)^6}\) 4) \(\sqrt[3]{0.008}\) 5) \(\sqrt[10]{-1}\)

Hints

- An odd root of a negative number can be real, but an even root cannot. - Check exact values by raising the proposed result to the radical index. - For an even index, \(\sqrt[n]{a^n}=|a|\).

Solution

1. \(\sqrt[4]{-81}\) has no real value because an even root of a negative number is not real. 2. \(\sqrt[5]{-32}=-2\) because \((-2)^5=-32\). 3. \(\sqrt[6]{(-2)^6}=|-2|=2\). 4. \(\sqrt[3]{0.008}=0.2\) because \((0.2)^3=0.008\). 5. \(\sqrt[10]{-1}\) has no real value because an even root of a negative number is not real.

Answer

1) Not real 2) \(-2\) 3) \(2\) 4) \(0.2\) 5) Not real
5246739
Simplify each expression under the given condition. a) \(\sqrt{(a-8)^2}\) when \(a\leq8\) b) \(\sqrt[3]{(b+5)^3}\) when \(b\geq-5\) c) \(\sqrt[4]{(c-2)^4}\) when \(c\leq2\) d) \(\sqrt[6]{(1-x)^6}\) when \(x\geq1\)

Hints

- Distinguish between even-index and odd-index radicals. - For an even index, use an absolute value when simplifying \(\sqrt[n]{u^n}\). - Use each given condition to determine the sign of the expression inside the absolute value.

Solution

1. \(\sqrt{(a-8)^2}=|a-8|\). Since \(a-8\leq0\), the result is \(8-a\). 2. For an odd index, \(\sqrt[3]{(b+5)^3}=b+5\). 3. \(\sqrt[4]{(c-2)^4}=|c-2|\). Since \(c-2\leq0\), the result is \(2-c\). 4. \(\sqrt[6]{(1-x)^6}=|1-x|\). Since \(1-x\leq0\), the result is \(x-1\).

Answer

a) \(8-a\) b) \(b+5\) c) \(2-c\) d) \(x-1\)
5247359
Evaluate each expression without a calculator. a) \(\sqrt[6]{125^2}\) b) \(\sqrt[4]{2.25^2}\) c) \(\sqrt[8]{16^2}\) d) \(\sqrt[6]{0.001^2}\)

Hints

- Rewrite each radical as a rational exponent and reduce the exponent. - Identify a familiar square, cube, or fourth power after simplifying. - Check each result by raising it to the appropriate power.

Solution

1. \(\sqrt[6]{125^2}=125^{\frac{2}{6}}=125^{\frac13}=\sqrt[3]{125}=5\). 2. \(\sqrt[4]{2.25^2}=2.25^{\frac{2}{4}}=\sqrt{2.25}=1.5\). 3. \(\sqrt[8]{16^2}=16^{\frac{2}{8}}=16^{\frac14}=\sqrt[4]{16}=2\). 4. \(\sqrt[6]{0.001^2}=0.001^{\frac{2}{6}}=0.001^{\frac13}=\sqrt[3]{0.001}=0.1\).

Answer

a) \(5\) b) \(1.5\) c) \(2\) d) \(0.1\)
5247409
Approximate \(\sqrt[5]{100}\) to the nearest tenth by systematic trial. Show the calculations you use to bracket the value and decide how to round.

Hints

- Find two consecutive integers whose fifth powers bracket \(100\). - Then test consecutive tenths. - Compare with the midpoint between the two tenths to determine the rounded value.

Solution

1. Since \(2^5=32\) and \(3^5=243\), the value lies between \(2\) and \(3\). 2. Test consecutive tenths: \((2.5)^5=97.65625\) and \((2.6)^5=118.81376\). Therefore \(2.5<\sqrt[5]{100}<2.6\). 3. To decide how to round, test the midpoint: \((2.55)^5\approx107.82\). Since \(100<107.82\), \(\sqrt[5]{100}<2.55\), so the value rounds to \(2.5\).

Answer

\(\sqrt[5]{100}\approx2.5\)
5247479
Consider the expressions \(A=\sqrt[4]{x^2}\) and \(B=\sqrt{|x|}\). a) Evaluate both expressions for \(x=16\) and for \(x=-16\). b) For \(x>0\), use rational exponents to show that the two expressions are equivalent. c) Explain why the absolute value in \(B\) is needed for the expression to be defined for every real \(x\), while the square in \(A\) already guarantees this.

Hints

- Square each input before taking the fourth root. - Rewrite a radical as a rational exponent and reduce the exponent. - Recall what an absolute value does to a negative number.

Solution

1. For \(x=16\), \(A=\sqrt[4]{16^2}=4\) and \(B=\sqrt{|16|}=4\). For \(x=-16\), \(A=\sqrt[4]{(-16)^2}=4\) and \(B=\sqrt{|-16|}=4\). 2. When \(x>0\), \(A=(x^2)^{\frac14}=x^{\frac24}=x^{\frac12}=\sqrt{x}\). Also, \(|x|=x\), so \(B=\sqrt{x}\). Thus \(A=B\). 3. In \(A\), the radicand \(x^2\) is nonnegative for every real \(x\). In \(B\), the absolute value makes the radicand nonnegative; without it, \(\sqrt{x}\) would not be real for negative \(x\).

Answer

a) Both expressions equal \(4\) for \(x=16\) and for \(x=-16\). b) \((x^2)^{\frac14}=x^{\frac12}=\sqrt{x}=\sqrt{|x|}\) for \(x>0\). c) The square in \(A\) and the absolute value in \(B\) each make the radicand nonnegative.
5247519
Simplify each radical expression as far as possible under the given condition. 1) \(\sqrt[6]{(b-3)^2}\) when \(b<3\) 2) \(\sqrt[10]{(x-1)^{10}}\) when \(x<1\)

Hints

- Reduce the radical index and exponent by their common factor. - An even-index root may introduce an absolute value. - Use each condition to determine the sign inside the absolute value.

Solution

1. \(\sqrt[6]{(b-3)^2}=\sqrt[3]{|b-3|}\). Since \(b<3\), \(b-3<0\), so \(|b-3|=3-b\). The result is \(\sqrt[3]{3-b}\). 2. \(\sqrt[10]{(x-1)^{10}}=|x-1|\). Since \(x<1\), \(x-1<0\), so \(|x-1|=1-x\).

Answer

1) \(\sqrt[3]{3-b}\) 2) \(1-x\)
5249019
Rewrite each expression using rational exponents, simplify, and then write the final result in radical form. Assume the variables are positive. 1) \(\sqrt[3]{7}\cdot\sqrt7\) 2) \(\frac{\sqrt[4]{x^3}}{\sqrt[8]{x}}\) 3) \(\sqrt[5]{a^2}\cdot\sqrt[10]{a}\)

Hints

- Rewrite each radical as a power with a fractional exponent. - Add exponents when multiplying and subtract when dividing like bases. - Use a common denominator for the exponent fractions. - Convert the simplified rational exponent back to a radical.

Solution

1. \(\sqrt[3]{7}\cdot\sqrt7=7^{\frac13+\frac12}=7^{\frac56}=\sqrt[6]{7^5}\). 2. \(\frac{\sqrt[4]{x^3}}{\sqrt[8]{x}}=x^{\frac34-\frac18}=x^{\frac58}=\sqrt[8]{x^5}\). 3. \(\sqrt[5]{a^2}\cdot\sqrt[10]{a}=a^{\frac25+\frac1{10}}=a^{\frac12}=\sqrt a\).

Answer

1) \(\sqrt[6]{7^5}\) 2) \(\sqrt[8]{x^5}\) 3) \(\sqrt a\)
5249079
Convert each expression to the other form: radical form or rational-exponent form. Assume all variables are positive. 1) \(\sqrt[5]{x^3}\) 2) \(a^{-\frac23}\) 3) \(\frac1{\sqrt[4]{y}}\) 4) \((m+n)^{\frac34}\)

Hints

- The radical index becomes the denominator of a rational exponent. - The exponent on the radicand becomes the numerator. - A negative exponent produces a reciprocal. - Treat a parenthesized sum as one base.

Solution

1. \(\sqrt[5]{x^3}=x^{\frac35}\). 2. \(a^{-\frac23}=\frac1{a^{\frac23}}=\frac1{\sqrt[3]{a^2}}\). 3. \(\frac1{\sqrt[4]{y}}=y^{-\frac14}\). 4. \((m+n)^{\frac34}=\sqrt[4]{(m+n)^3}\).

Answer

1) \(x^{\frac35}\) 2) \(\frac1{\sqrt[3]{a^2}}\) 3) \(y^{-\frac14}\) 4) \(\sqrt[4]{(m+n)^3}\)
5249099
Convert each expression to the other form, using either a rational exponent or a radical. Evaluate when possible. Assume \(b>0\). a) \(\sqrt[5]{y^2}\) b) \(27^{\frac23}\) c) \(b^{-0.75}\)

Hints

- Match the radical index with the denominator of the exponent. - Rewrite the decimal exponent as a fraction. - For part b), taking the cube root first makes the calculation simple. - A negative exponent produces a reciprocal.

Solution

1. \(\sqrt[5]{y^2}=y^{\frac25}\). 2. \(27^{\frac23}=(\sqrt[3]{27})^2=3^2=9\). 3. Since \(-0.75=-\frac34\), \(b^{-0.75}=b^{-\frac34}=\frac1{\sqrt[4]{b^3}}\).

Answer

a) \(y^{\frac25}\) b) \(9\) c) \(\frac1{\sqrt[4]{b^3}}\)
5249139
Determine whether each equation is true or false. Correct each false equation. 1. \((\sqrt[5]{15})^5=15\) 2. \((\sqrt2)^6=8\) 3. \((\sqrt[3]{3})^6=6\) 4. \(\sqrt[4]{5^8}=25\)

Hints

- Rewrite each radical as a rational exponent. - Multiply exponents when raising a power to another power. - Compare the radical index with the outside exponent.

Solution

1. True: \((\sqrt[5]{15})^5=(15^{\frac15})^5=15\). 2. True: \((\sqrt2)^6=(2^{\frac12})^6=2^3=8\). 3. False: \((\sqrt[3]{3})^6=(3^{\frac13})^6=3^2=9\). The corrected result is \(9\). 4. True: \(\sqrt[4]{5^8}=5^{\frac84}=5^2=25\).

Answer

1. True 2. True 3. False; the correct value is \(9\). 4. True
5249219
Simplify each expression completely. In part b), assume \(y\ge0\). a) \((\sqrt[6]{x^4})^3\) b) \((-2\sqrt[4]{y^3})^4\) c) \((0.5\sqrt[3]{2a^2})^3\)

Hints

- Rewrite each radical as a rational exponent. - Apply an outside exponent to every factor in a product. - Track the sign of a negative factor raised to an even or odd power.

Solution

1. \((\sqrt[6]{x^4})^3=(x^4)^{\frac36}=x^2\). 2. \((-2\sqrt[4]{y^3})^4=(-2)^4(\sqrt[4]{y^3})^4=16y^3\). 3. \((0.5\sqrt[3]{2a^2})^3=(0.5)^3(\sqrt[3]{2a^2})^3=0.125(2a^2)=0.25a^2\).

Answer

a) \(x^2\) b) \(16y^3\) c) \(0.25a^2\)
5249239
Evaluate or simplify each expression. In part c, assume \(x\geq0\). a) \((-\sqrt[4]{10})^4\) b) \((-\sqrt[5]{3})^5\) c) \((-2\sqrt{x})^2\) d) \((\sqrt[3]{y^2})^6\)

Hints

- An even outer exponent removes a negative sign; an odd outer exponent preserves it. - Rewrite radicals as rational exponents when useful. - Apply the outer power to every factor in a product.

Solution

1. \((-\sqrt[4]{10})^4=(\sqrt[4]{10})^4=10\) because the outer exponent is even. 2. \((-\sqrt[5]{3})^5=-(\sqrt[5]{3})^5=-3\) because the outer exponent is odd. 3. \((-2\sqrt{x})^2=(-2)^2(\sqrt{x})^2=4x\). 4. \((\sqrt[3]{y^2})^6=(y^{\frac23})^6=y^4\).

Answer

a) \(10\) b) \(-3\) c) \(4x\) d) \(y^4\)
5249259
Simplify each expression completely. Write the result without rational exponents, using radicals when needed. In part 1), assume \(a\ge0\). 1) \((5a^2\sqrt a)^2\) 2) \((b^3\sqrt[3]{b})^2\)

Hints

- Apply the outside exponent to every factor. - Rewrite a radical as a rational exponent while simplifying. - Add exponents when multiplying powers with the same base. - Convert any remaining fractional exponent back to a radical.

Solution

1. \((5a^2\sqrt a)^2=5^2(a^2)^2(\sqrt a)^2=25a^5\). 2. \((b^3\sqrt[3]{b})^2=b^6(\sqrt[3]{b})^2=b^6\sqrt[3]{b^2}\).

Answer

1) \(25a^5\) 2) \(b^6\sqrt[3]{b^2}\)
5249479
Evaluate each expression using properties of powers and roots. a) \((\sqrt{3.5\cdot4+11})^2\) b) \((\sqrt[3]{5^2+2})^3\) c) \((\sqrt{x+\sqrt{x}})^2\) for \(x\geq0\)

Hints

- A radical followed by the matching power returns its nonnegative radicand. - Simplify the expression inside each radical. - Check that the variable condition makes the radical defined.

Solution

1. \((\sqrt{3.5\cdot4+11})^2=3.5\cdot4+11=14+11=25\). 2. \((\sqrt[3]{5^2+2})^3=5^2+2=25+2=27\). 3. Because \(x\geq0\), the radicand is defined and nonnegative. Therefore \((\sqrt{x+\sqrt{x}})^2=x+\sqrt{x}\).

Answer

a) \(25\) b) \(27\) c) \(x+\sqrt{x}\)
5249489
Simplify each expression as far as possible. Assume all variable values make the expressions defined. a) \((3\sqrt{y+2})^2\) b) \((k^2\sqrt[3]{k})^3\) c) \(\frac{(\sqrt{50})^2-(\sqrt2)^2}{(\sqrt[3]{4})^3}\)

Hints

- Apply an outer power to every factor in a product. - Multiply exponents when raising a power to a power. - Simplify the numerator and denominator separately before dividing.

Solution

1. \((3\sqrt{y+2})^2=3^2(\sqrt{y+2})^2=9(y+2)=9y+18\). 2. \((k^2\sqrt[3]{k})^3=(k^2)^3(\sqrt[3]{k})^3=k^6\cdot k=k^7\). 3. \(\frac{(\sqrt{50})^2-(\sqrt2)^2}{(\sqrt[3]{4})^3}=\frac{50-2}{4}=12\).

Answer

a) \(9y+18\) b) \(k^7\) c) \(12\)
5249779
Simplify each expression and write the result as a single power with a rational exponent. In part a), assume \(a\ge0\). a) \(\sqrt[3]{a^2\sqrt[4]{a}}\) b) \(\sqrt{8\sqrt[3]{2}}\)

Hints

- Work from the inner radical outward. - Add exponents when multiplying powers with the same base. - Multiply exponents when applying the outer radical. - Rewrite \(8\) as a power of \(2\).

Solution

1. \(\sqrt[3]{a^2\sqrt[4]{a}}=\left(a^2a^{\frac14}\right)^{\frac13}=a^{\left(2+\frac14\right)\frac13}=a^{\frac34}\). 2. Since \(8=2^3\), \(\sqrt{8\sqrt[3]{2}}=\left(2^3\cdot2^{\frac13}\right)^{\frac12}=2^{\left(3+\frac13\right)\frac12}=2^{\frac53}\).

Answer

a) \(a^{\frac34}\) b) \(2^{\frac53}\)
5249919
Simplify each expression completely. a) \((\sqrt7)^{-2}\) b) \((\sqrt[3]{a^6})^{\frac12}\), where \(a\ge0\) c) \(\left(\sqrt[3]{\frac1{64}}\right)^{-2}\)

Hints

- Rewrite radicals as rational exponents. - Multiply exponents in a power raised to another power. - A negative exponent takes the reciprocal. - Simplify the expression inside parentheses before applying the outside exponent.

Solution

1. \((\sqrt7)^{-2}=(7^{\frac12})^{-2}=7^{-1}=\frac17\). 2. \((\sqrt[3]{a^6})^{\frac12}=(a^2)^{\frac12}=a\) because \(a\ge0\). 3. \(\sqrt[3]{\frac1{64}}=\frac14\), so \(\left(\frac14\right)^{-2}=4^2=16\).

Answer

a) \(\frac17\) b) \(a\) c) \(16\)
5249999
Simplify each expression and write the result as a single power with a rational exponent. In part a), assume \(x\ne0\), and in part b), assume \(a>0\). a) \(\frac{x^3}{\sqrt[5]{x^2}}\) b) \(\frac{\sqrt a\sqrt[3]{a}}a\)

Hints

- Rewrite each radical as a rational exponent. - Add exponents when multiplying powers with the same base. - Subtract the denominator exponent. - Write a variable with no visible exponent as a first power.

Solution

1. \(\frac{x^3}{\sqrt[5]{x^2}}=x^{3-\frac25}=x^{\frac{13}{5}}\). 2. \(\frac{\sqrt a\sqrt[3]{a}}a=a^{\frac12+\frac13-1}=a^{-\frac16}\).

Answer

a) \(x^{\frac{13}{5}}\) b) \(a^{-\frac16}\)
5253499
Find the real solution set for each equation. a) \((3x+10)^{\frac{1}{3}}=4\) b) \((2x-5)^{\frac{1}{2}}=(x+1)^{\frac{1}{2}}\)

Hints

- Undo a power of \(\frac{1}{3}\) by cubing both sides. - Undo a power of \(\frac{1}{2}\) by squaring both sides. - Check that square-root radicands are nonnegative.

Solution

1. Cube both sides of part a: \(3x+10=4^3=64\). Then \(3x=54\), so \(x=18\). 2. Square both sides of part b: \(2x-5=x+1\), so \(x=6\). 3. Check the original equation in part b. When \(x=6\), both radicands equal \(7\), so the solution is valid.

Answer

a) \(\{18\}\) b) \(\{6\}\)
5260399
Without using a calculator, decide whether each expression is greater than \(1\), equal to \(1\), or less than \(1\). Briefly justify each answer using properties of exponential expressions. a) \(1.05^{12}\) b) \(0.92^5\) c) \(\left(\frac{1}{2}\right)^{-3}\) d) \(\left(\frac{5}{4}\right)^{-0.2}\) e) \((\sqrt{2}-1)^0\)

Hints

- Compare the base with \(1\). - Consider whether the exponent is positive, negative, or zero. - Recall the meaning of a negative exponent. - Recall the zero-exponent rule.

Solution

1. In a), the base is greater than \(1\) and the exponent is positive, so the value is greater than \(1\). 2. In b), the base is between \(0\) and \(1\) and the exponent is positive, so the value is less than \(1\). 3. In c), a negative exponent takes the reciprocal: \(\left(\frac{1}{2}\right)^{-3}=2^3\), so the value is greater than \(1\). 4. In d), \(\left(\frac{5}{4}\right)^{-0.2}=\frac{1}{\left(\frac{5}{4}\right)^{0.2}}\). The denominator is greater than \(1\), so the value is less than \(1\). 5. In e), any nonzero base raised to the zero power equals \(1\). Since \(\sqrt{2}-1\ne0\), the value equals \(1\).

Answer

a) Greater than \(1\) b) Less than \(1\) c) Greater than \(1\) d) Less than \(1\) e) Equal to \(1\)
5101609
Show that for a positive number \(a\) and \(m\in\mathbb{N}\), \(\sqrt{a^{4m}}=a^{2m}\). Then use the relationship to simplify or evaluate: a) \(\sqrt{3^4}\) b) \(\sqrt{2^{12}}\) c) \(\sqrt{x^{16}}\), where \(x>0\)

Hints

- Rewrite a square root as an exponent of \(\frac{1}{2}\). - Multiply exponents for a power of a power. - Use the positivity condition to avoid sign ambiguity.

Solution

1. Rewrite the square root using a rational exponent: \(\sqrt{a^{4m}}=(a^{4m})^{\frac{1}{2}}=a^{2m}\). 2. \(\sqrt{3^4}=3^2=9\). 3. \(\sqrt{2^{12}}=2^6=64\). 4. \(\sqrt{x^{16}}=x^8\) for \(x>0\).

Answer

In general, \(\sqrt{a^{4m}}=a^{2m}\). a) \(9\) b) \(64\) c) \(x^8\)
5143279
Find the missing exponent \(n\) so that each equation is true for \(x>0\). a) \(\sqrt{x^n}=x^7\) b) \(\sqrt{3^n}=81\) c) \(\sqrt[3]{x^{12}}=x^n\) d) \(\sqrt{x^4x^n}=x^5\)

Hints

- Rewrite each radical as a rational exponent. - Express both sides with the same base. - Equate exponents after simplifying.

Solution

1. In part a, \(x^{\frac n2}=x^7\), so \(n=14\). 2. Since \(81=3^4\), \(3^{\frac n2}=3^4\), so \(n=8\). 3. \(\sqrt[3]{x^{12}}=x^4\), so \(n=4\). 4. \(\sqrt{x^{4+n}}=x^{\frac{4+n}{2}}=x^5\), so \(4+n=10\) and \(n=6\).

Answer

a) \(n=14\) b) \(n=8\) c) \(n=4\) d) \(n=6\)
5144229
Consider powers of ten of the form \(10^{2n}\), where \(n\in\mathbb{Z}\). 1. Explain why \(\sqrt{10^{2n}}=10^n\). 2. Apply the rule and write each result as a decimal. a) \(\sqrt{10^6}\) b) \(\sqrt{10^{-4}}\) c) \(\sqrt{0.000001}\)

Hints

- Rewrite a square root using exponent \(\frac{1}{2}\). - Use the power-of-a-power property. - Rewrite the decimal as a power of ten before taking its square root. - Taking a square root divides an exponent by \(2\).

Solution

1. A square root can be written using exponent \(\frac{1}{2}\). Therefore, \(\sqrt{10^{2n}}=(10^{2n})^{1/2}=10^{2n\cdot\frac{1}{2}}=10^n\). 2. For a), \(\sqrt{10^6}=10^3=1000\). 3. For b), \(\sqrt{10^{-4}}=10^{-2}=0.01\). 4. For c), \(0.000001=10^{-6}\), so \(\sqrt{0.000001}=10^{-3}=0.001\).

Answer

1. \(\sqrt{10^{2n}}=(10^{2n})^{1/2}=10^n\) 2. a) \(1000\) b) \(0.01\) c) \(0.001\)
5144249
A student claims that \(\sqrt{x^k}=x^{k/2}\) for every real number \(x\) and every positive integer \(k\). a) Test the claim for \(x=4\) and \(k=2\). b) Test it for \(x=-3\) and \(k=2\). c) State a correct rule for \(\sqrt{x^k}\). Consider \(x\ge0\), negative \(x\) with even \(k\), and negative \(x\) with odd \(k\).

Hints

- A principal square root is always nonnegative. - Use \(\sqrt{u^2}=|u|\). - Determine the sign of a power with a negative base for even and odd exponents.

Solution

1. For \(x=4\) and \(k=2\), \(\sqrt{4^2}=4=4^{2/2}\), so the claim works in this case. 2. For \(x=-3\) and \(k=2\), \(\sqrt{(-3)^2}=3\), but \((-3)^{2/2}=-3\). The claim is false. 3. If \(x\ge0\), then \(\sqrt{x^k}=x^{k/2}\). 4. If \(x<0\) and \(k\) is even, then \(\sqrt{x^k}=|x|^{k/2}\). 5. If \(x<0\) and \(k\) is odd, then \(x^k<0\), so \(\sqrt{x^k}\) is not a real number.

Answer

a) The claim works: \(\sqrt{4^2}=4\). b) The claim fails: \(\sqrt{(-3)^2}=3\ne-3\). c) For \(x\ge0\), \(\sqrt{x^k}=x^{k/2}\). For \(x<0\) and even \(k\), \(\sqrt{x^k}=|x|^{k/2}\). For \(x<0\) and odd \(k\), the expression is not real.
5148959
Find \(x\). In parts a, b, and d, assume \(x>0\). In part c, \(x\) is an integer radical index with \(x\ge2\). a) \(\sqrt[4]{x}=3\) b) \(x^{\frac{3}{2}}=64\) c) \(\sqrt[x]{243}=3\) d) \(x^3=\frac{27}{1000}\)

Hints

- Undo a radical or power by applying the inverse exponent. - Rewrite \(243\) as a power of \(3\). - Take the cube root of the numerator and denominator separately in part d.

Solution

1. Raise both sides of part a to the fourth power: \(x=3^4=81\). 2. Raise both sides of part b to the power \(\frac{2}{3}\): \(x=64^{\frac{2}{3}}=16\). 3. Rewrite part c as \(3^x=243\). Since \(243=3^5\), \(x=5\). 4. Take the cube root in part d: \(x=\sqrt[3]{\frac{27}{1000}}=\frac{3}{10}=0.3\).

Answer

a) \(x=81\) b) \(x=16\) c) \(x=5\) d) \(x=0.3\)
5149009
Determine which expressions are equivalent to \(a^2\) for \(a>0\). Justify each choice. 1. \(\sqrt[3]{a^6}\) 2. \(\sqrt a\cdot a^{1.5}\) 3. \((a^4)^{\frac14}\) 4. \(\frac{a^3}{\sqrt{a^2}}\)

Hints

- Rewrite radicals as rational exponents. - Add or subtract exponents for products and quotients with the same base. - Use \(a>0\) when simplifying \(\sqrt{a^2}\).

Solution

1. \(\sqrt[3]{a^6}=a^2\), so expression 1 is equivalent. 2. \(\sqrt a\cdot a^{1.5}=a^{0.5+1.5}=a^2\), so expression 2 is equivalent. 3. \((a^4)^{\frac14}=a\), so expression 3 is not equivalent. 4. Since \(a>0\), \(\sqrt{a^2}=a\). Thus \(\frac{a^3}{a}=a^2\), so expression 4 is equivalent.

Answer

Expressions 1, 2, and 4 are equivalent to \(a^2\). Expression 3 equals \(a\).
5149039
Solve each equation for all real values of \(x\). Give each answer in exact form and as a decimal rounded to two decimal places. a) \(3x^4-25=218\) b) \(10-\frac{1}{2}x^3=50\) c) \(0.2x^5+7=5\)

Hints

- Isolate the power of \(x\) first. - Undo the power by taking the corresponding root. - An even power can lead to two real solutions, while an odd power has one real solution. - Round only after finding the exact value.

Solution

1. For \(3x^4-25=218\), add \(25\) and divide by \(3\): \(x^4=81\). Because the exponent is even, \(x=\pm\sqrt[4]{81}=\pm3\), so \(x\approx\pm3.00\). 2. For \(10-\frac{1}{2}x^3=50\), subtract \(10\) and multiply by \(-2\): \(x^3=-80\). Thus \(x=\sqrt[3]{-80}=-\sqrt[3]{80}\approx-4.31\). 3. For \(0.2x^5+7=5\), subtract \(7\) and divide by \(0.2\): \(x^5=-10\). Thus \(x=\sqrt[5]{-10}=-\sqrt[5]{10}\approx-1.58\).

Answer

a) \(x=\pm3\), so \(x\approx\pm3.00\) b) \(x=-\sqrt[3]{80}\approx-4.31\) c) \(x=-\sqrt[5]{10}\approx-1.58\)
5149049
Consider equations of the form \(ax^n+b=c\). a) Solve \(5x^6-20=100\) for all real values of \(x\). Round to two decimal places. b) What value of \(c\) makes \(5x^6-20=c\) have exactly one real solution, \(x=0\)? c) Solve \(2(x^3-5)=40\) exactly.

Hints

- Isolate the power in each equation. - In part b, determine what the right side must be after isolating \(x^6\) so that \(x=0\) is the only solution. - In part c, divide by the factor outside the parentheses before taking a root.

Solution

1. For part a, add \(20\) and divide by \(5\): \(x^6=24\). Because the exponent is even, \(x=\pm\sqrt[6]{24}\approx\pm1.70\). 2. For part b, the only way an even power equals zero is when \(x=0\). Set \(x^6=0\): from \(5x^6-20=c\), this gives \(c=-20\). 3. For part c, divide by \(2\) and add \(5\): \(x^3=25\). Therefore, \(x=\sqrt[3]{25}\).

Answer

a) \(x\approx\pm1.70\) b) \(c=-20\) c) \(x=\sqrt[3]{25}\)
5149069
Compare each pair without a calculator. Insert \(<\), \(>\), or \(=\). a) \(\sqrt{0.49}\ \square\ 0.07\) b) \(\sqrt[3]{27}\ \square\ \sqrt{9}\) c) \(\sqrt[4]{\frac{1}{16}}\ \square\ \frac{1}{4}\) d) \(\sqrt{20}\ \square\ 4.5\)

Hints

- Evaluate perfect roots when possible. - For two positive quantities, squaring can make a comparison easier. - Pay close attention to decimal place value.

Solution

1. \(\sqrt{0.49}=0.7\), and \(0.7>0.07\). 2. \(\sqrt[3]{27}=3\) and \(\sqrt{9}=3\), so they are equal. 3. \(\sqrt[4]{\frac{1}{16}}=\frac{1}{2}\), and \(\frac{1}{2}>\frac{1}{4}\). 4. Both numbers are positive. Since \((4.5)^2=20.25>20\), \(\sqrt{20}<4.5\).

Answer

a) \(>\) b) \(=\) c) \(>\) d) \(<\)
5149099
Find all real solutions for \(x\). a) \(2x^4-32=0\) b) \(\frac{1}{3}x^3+10=1\) c) \(5x^6+12=7\)

Hints

- Isolate the power of \(x\). - Then take the corresponding root. - Check the sign of the isolated value and whether the exponent is even or odd.

Solution

1. For \(2x^4-32=0\), add \(32\) and divide by \(2\): \(x^4=16\). Therefore, \(x=\pm2\). 2. For \(\frac{1}{3}x^3+10=1\), subtract \(10\) and multiply by \(3\): \(x^3=-27\). Therefore, \(x=-3\). 3. For \(5x^6+12=7\), subtract \(12\) and divide by \(5\): \(x^6=-1\). An even power cannot be negative for real \(x\), so there is no real solution.

Answer

a) \(x=\pm2\) b) \(x=-3\) c) No real solution
5149109
Find the real solution set for each equation. Give answers as fractions or decimals when needed. a) \(x^4=\frac{1}{81}\) b) \(x^6=729\) c) \(x^3=-0.125\) d) \(2x^5+64=0\)

Hints

- Rewrite familiar decimals or fractions as powers when useful. - Include both signs when an even power equals a positive number. - For part d, isolate \(x^5\) before taking the fifth root.

Solution

1. Since \(\left(\frac{1}{3}\right)^4=\frac{1}{81}\) and the exponent is even, \(x=\pm\frac{1}{3}\). 2. Since \(3^6=729\) and the exponent is even, \(x=\pm3\). 3. Since \((-0.5)^3=-0.125\), \(x=-0.5\). 4. Subtract \(64\) and divide by \(2\): \(x^5=-32\). Since \((-2)^5=-32\), \(x=-2\).

Answer

a) \(\left\{-\frac{1}{3},\frac{1}{3}\right\}\) b) \(\{-3,3\}\) c) \(\{-0.5\}\) d) \(\{-2\}\)
5149129
Consider the equation \(x^n=100\). a) Find all real solutions when \(n=2\) and when \(n=4\). Round the solutions for \(n=4\) to two decimal places. b) As \(n\) increases while the right side remains \(100\), what happens to the positive solution? Explain why. c) For which positive even integers \(n\) is the positive solution between \(1.5\) and \(2.0\)? Test values systematically.

Hints

- Write the positive solution as \(100^{\frac{1}{n}}\). - Think about how a base greater than \(1\) behaves when its exponent increases. - For part c, test consecutive positive even exponents and use the decreasing pattern to know when to stop.

Solution

1. When \(n=2\), \(x=\pm\sqrt{100}=\pm10\). When \(n=4\), \(x=\pm\sqrt[4]{100}=\pm\sqrt{10}\approx\pm3.16\). 2. The positive solution is \(100^{\frac{1}{n}}\). As \(n\) increases, a number greater than \(1\) needs a smaller base to produce the same value \(100\). Therefore, the positive solution decreases and approaches \(1\). 3. Test positive even exponents: \(100^{\frac{1}{6}}\approx2.15\), \(100^{\frac{1}{8}}\approx1.78\), \(100^{\frac{1}{10}}\approx1.58\), and \(100^{\frac{1}{12}}\approx1.47\). Since the positive solution decreases as \(n\) increases, only \(n=8\) and \(n=10\) give values between \(1.5\) and \(2.0\).

Answer

a) For \(n=2\), \(x=\pm10\). For \(n=4\), \(x=\pm\sqrt{10}\approx\pm3.16\). b) The positive solution decreases toward \(1\). c) \(n=8\) and \(n=10\)
5149139
Use properties of equations of the form \(x^n=c\). 1. An equation \(x^n=c\) has \(x=-3\) as its only real solution. Give two different pairs of values for the positive integer \(n\) and the real number \(c\) that satisfy this condition. 2. An equation \(x^n=c\) has exactly the two real solutions \(x=2\) and \(x=-2\). What conditions must \(n\) and \(c\) satisfy? Give one example. 3. Solve \(0.5x^3+10=510\) step by step.

Hints

- Relate the number of real solutions to whether \(n\) is even or odd. - For the second part, substitute both \(2\) and \(-2\) into \(x^n\). - In the last part, isolate the power term before taking a root.

Solution

1. To make \(x=-3\) the only real solution, \(n\) must be odd and \(c=(-3)^n\). Two possible pairs are \((n, c)=(1, -3)\) and \((n, c)=(3, -27)\). 2. To have the symmetric solutions \(x=\pm2\), \(n\) must be a positive even integer and \(c=2^n\). For example, \(n=2\) and \(c=4\). 3. Subtract \(10\): \(0.5x^3=500\). Divide by \(0.5\): \(x^3=1000\). Take the cube root: \(x=10\).

Answer

1. Sample pairs: \((n, c)=(1, -3)\) and \((n, c)=(3, -27)\) 2. \(n\) must be a positive even integer and \(c=2^n\). For example, \(n=2\) and \(c=4\). 3. \(x=10\)
5149189
Find all real solutions by rewriting each equation in the form \(x^n=c\). a) \(3x^4=48\) b) \(4x^3+32=0\) c) \(\frac{1}{2}x^5-12=4\) d) \(100-x^2=19\)

Hints

- Isolate the power term first. - Use inverse operations in reverse order. - When the exponent is even and the isolated value is positive, include both signs.

Solution

1. Divide \(3x^4=48\) by \(3\): \(x^4=16\). Therefore, \(x=\pm2\). 2. Subtract \(32\) and divide by \(4\): \(x^3=-8\). Therefore, \(x=-2\). 3. Add \(12\) and multiply by \(2\): \(x^5=32\). Therefore, \(x=2\). 4. Subtract \(100\) and divide by \(-1\): \(x^2=81\). Therefore, \(x=\pm9\).

Answer

a) \(x=\pm2\) b) \(x=-2\) c) \(x=2\) d) \(x=\pm9\)
5149249
Simplify each expression using exponent properties. In part a, assume \(x\geq0\); in part b, assume \(y\neq0\). a) \(x^{\frac12}x^{\frac14}x^{\frac14}\) b) \(\frac{\sqrt[3]{y^5}}{\sqrt[3]{y^2}}\) c) \(\frac{\sqrt[4]{81^3}}{3^2}\)

Hints

- Add exponents when multiplying powers with the same base. - Combine cube roots in a quotient. - Rewrite \(81\) as a power of \(3\).

Solution

1. \(x^{\frac12}x^{\frac14}x^{\frac14}=x^1=x\). 2. \(\frac{\sqrt[3]{y^5}}{\sqrt[3]{y^2}}=\sqrt[3]{y^3}=y\). 3. Since \(81=3^4\), \(\sqrt[4]{81^3}=\sqrt[4]{3^{12}}=3^3\). Dividing by \(3^2\) gives \(3\).

Answer

a) \(x\) b) \(y\) c) \(3\)
5149259
Compare the two values in each pair without a calculator. Rewrite each expression as a whole number. a) \(A=\sqrt[3]{2}\sqrt[3]{4}\) or \(B=\sqrt2\sqrt8\) b) \(C=27^{\frac23}\) or \(D=16^{\frac34}\)

Hints

- Combine radicals with the same index. - Interpret \(a^{\frac{m}{n}}\) as an \(n\)th root raised to the \(m\)th power. - Evaluate the root before the remaining power when that keeps the numbers small.

Solution

1. \(A=\sqrt[3]{2\cdot4}=\sqrt[3]{8}=2\). 2. \(B=\sqrt{2\cdot8}=\sqrt{16}=4\). Therefore \(B>A\). 3. \(C=(\sqrt[3]{27})^2=3^2=9\). 4. \(D=(\sqrt[4]{16})^3=2^3=8\). Therefore \(C>D\).

Answer

a) \(B>A\), because \(B=4\) and \(A=2\). b) \(C>D\), because \(C=9\) and \(D=8\).
5149299
A sculptor casts bronze models of a statue. The mass \(m\), in grams, of a model with height \(h\), in centimeters, is given by \(m=0.05h^3\). Find the height of a model with a mass of exactly \(3.2\,\text{kg}\).

Hints

- Express the mass in grams before substituting. - Isolate \(h^3\), then take a cube root.

Solution

1. Convert the mass to grams: \(3.2\,\text{kg}=3200\,\text{g}\). 2. Substitute the mass into the formula: \(3200=0.05h^3\). 3. Divide by \(0.05\): \(h^3=64{,}000\). 4. Take the cube root: \(h=\sqrt[3]{64{,}000}=40\).

Answer

The model is \(40\,\text{cm}\) tall.
5149309
The power \(P\), in kilowatts, produced by a wind turbine can be approximated by \(P=0.2v^3\), where \(v\) is the wind speed in meters per second. a) Find the wind speed needed to produce \(500\,\text{kW}\). Round to the nearest tenth. b) By what percent does the power decrease when the wind speed is cut in half? Justify your answer using the formula.

Hints

- In part a, isolate \(v^3\) before taking a cube root. - In part b, replace \(v\) by \(0.5v\) and compare the resulting expression with the original formula.

Solution

1. For part a, substitute \(P=500\): \(500=0.2v^3\). 2. Divide by \(0.2\): \(v^3=2500\). Therefore, \(v=\sqrt[3]{2500}\approx13.572\), which rounds to \(13.6\,\text{m/s}\). 3. For part b, replace \(v\) with \(0.5v\): \(P_{\text{new}}=0.2(0.5v)^3=0.125(0.2v^3)=0.125P_{\text{original}}\). 4. The new power is \(12.5\%\) of the original power, so the decrease is \(100\%-12.5\%=87.5\%\).

Answer

a) \(13.6\,\text{m/s}\) b) The power decreases by \(87.5\%\).
5149359
A solid iron cube has a mass of \(20\,\text{kg}\). The density of iron is approximately \(7.87\,\text{g/cm}^3\). Use \(m=\rho V\), where \(m\) is mass, \(\rho\) is density, and \(V\) is volume. a) Find the edge length of the cube in centimeters. Round to the nearest hundredth. b) What would the mass of an iron cube with twice the edge length be? Give the answer in kilograms.

Hints

- Convert the mass to grams so its unit matches the density. - Use density to find volume, then take the cube root to find the edge length. - For part b, determine the volume scale factor when each dimension doubles.

Solution

1. Convert the mass: \(20\,\text{kg}=20{,}000\,\text{g}\). 2. Use \(V=\frac{m}{\rho}\): \(V=\frac{20000}{7.87}\approx2541.30\,\text{cm}^3\). 3. For a cube, \(V=a^3\), so \(a=\sqrt[3]{2541.30}\approx13.65\,\text{cm}\). 4. Doubling every edge multiplies the volume, and therefore the mass, by \(2^3=8\). The new mass is \(8\cdot20\,\text{kg}=160\,\text{kg}\).

Answer

a) Approximately \(13.65\,\text{cm}\) b) \(160\,\text{kg}\)
5149369
A small gold cube has an edge length of \(5.0\,\text{cm}\). The density of gold is approximately \(19.3\,\text{g/cm}^3\). a) Find the mass of the cube in grams. b) The cube is melted, and another \(500\,\text{g}\) of gold is added. The gold is cast as a new cube. Find the new edge length and the percent increase in edge length. Use \(m=\rho V\), where \(m\) is mass, \(\rho\) is density, and \(V\) is volume.

Hints

- Find the original volume from the edge length, then use density to calculate the original mass. - Add the extra mass, then use density to find the new volume. - Take a cube root, equivalently a \(1/3\) power, to find the new edge length. - Compare the change in edge length with the original edge length to find the percent increase.

Solution

1. The original volume is \(V_1=(5.0\,\text{cm})^3=125\,\text{cm}^3\). 2. The original mass is \(m_1=125\cdot19.3=2412.5\,\text{g}\). 3. The new mass is \(m_2=2412.5+500=2912.5\,\text{g}\), so the new volume is \(V_2=\frac{2912.5}{19.3}\approx150.91\,\text{cm}^3\). 4. The new edge length is \(a_2=V_2^{1/3}=\sqrt[3]{V_2}\approx5.324\,\text{cm}\), or about \(5.32\,\text{cm}\). 5. Using the unrounded value of \(a_2\), the percent increase is \(\frac{a_2-5.0}{5.0}\cdot100\%\approx6.48\%\), which is about \(6.5\%\).

Answer

a) \(2412.5\,\text{g}\) b) The new edge length is approximately \(5.32\,\text{cm}\), an increase of approximately \(6.5\%\).
5149379
A cylindrical oil tank is designed so that its height \(h\) equals its radius \(r\). a) Write a formula for the volume \(V\) in terms of \(r\). b) Find the radius needed for the tank to hold exactly \(1000\,\text{L}\). Give the answer in centimeters, rounded to the nearest hundredth. c) If the radius is tripled and the condition \(h=r\) is maintained, by what factor does the volume change? Explain.

Hints

- Substitute \(h=r\) into the cylinder volume formula. - Convert liters to cubic centimeters before solving. - Isolate \(r^3\), then take a cube root, equivalently raise both sides to the \(1/3\) power. - Expand \((3r)^3\) to determine the scale factor.

Solution

1. The volume of a cylinder is \(V=\pi r^2h\). Since \(h=r\), \(V=\pi r^3\). 2. Convert the volume: \(1000\,\text{L}=1{,}000{,}000\,\text{cm}^3\). 3. Solve \(1{,}000{,}000=\pi r^3\): \(r^3=\frac{1000000}{\pi}\), so \(r=\left(\frac{1000000}{\pi}\right)^{1/3}=\sqrt[3]{\frac{1000000}{\pi}}\approx68.28\,\text{cm}\). 4. If \(r\) is replaced by \(3r\), then \(V_{\text{new}}=\pi(3r)^3=27\pi r^3=27V\).

Answer

a) \(V=\pi r^3\) b) \(r\approx68.28\,\text{cm}\) c) The volume is multiplied by \(27\).
5149429
Order the four values from least to greatest. Justify the order by rewriting each expression. \(A=16^{0.25}\) \(B=\left(\frac19\right)^{-0.5}\) \(C=\sqrt[3]{27^2}\) \(D=25^{-0.5}\)

Hints

- Convert decimal exponents to fractions. - A negative exponent takes the reciprocal. - Evaluate each exact value before comparing.

Solution

1. \(A=16^{\frac14}=2\). 2. \(B=9^{\frac12}=3\). 3. \(C=(\sqrt[3]{27})^2=9\). 4. \(D=\frac1{\sqrt{25}}=\frac15=0.2\). 5. Therefore \(D<A<B<C\).

Answer

\(D<A<B<C\)
5149469
Simplify the expression. Give the final result in both exponent form and radical form. Assume \(a>0\). \(\frac{\sqrt[3]{a^2}\sqrt[4]{a}}{\sqrt[12]{a^5}}\)

Hints

- Rewrite all radicals as rational exponents. - Use a common denominator for the exponent fractions. - Add exponents in the numerator and subtract the denominator exponent.

Solution

1. Rewrite each radical as a rational exponent: \(a^{\frac23}a^{\frac14}/a^{\frac5{12}}\). 2. Combine exponents: \(\frac23+\frac14-\frac5{12}=\frac8{12}+\frac3{12}-\frac5{12}=\frac12\). 3. The expression is \(a^{\frac12}=\sqrt a\).

Answer

Exponent form: \(a^{\frac12}\) Radical form: \(\sqrt a\)
5149489
Determine whether each statement is true or false for \(x>0\). Justify your answer by rewriting both sides with rational exponents. a) \(\sqrt[6]{x^9}=\sqrt{x^3}\) b) \(\sqrt[4]{x^2}=\sqrt[8]{x^6}\) c) \(\frac1{\sqrt[3]{x}}=\sqrt[6]{x^{-2}}\)

Hints

- Rewrite every radical as a rational exponent. - Reduce each exponent fraction. - With the same positive base, compare the exponents.

Solution

1. \(\sqrt[6]{x^9}=x^{\frac96}=x^{\frac32}\), and \(\sqrt{x^3}=x^{\frac32}\). The statement is true. 2. \(\sqrt[4]{x^2}=x^{\frac12}\), while \(\sqrt[8]{x^6}=x^{\frac34}\). The statement is false. 3. \(\frac1{\sqrt[3]{x}}=x^{-\frac13}\), and \(\sqrt[6]{x^{-2}}=x^{-\frac26}=x^{-\frac13}\). The statement is true.

Answer

a) True b) False c) True
5149519
Order the four numbers from least to greatest without first using a calculator. Justify the order by comparing bases and radical indices. Then verify with decimal approximations rounded to two decimal places. \(a=\sqrt[3]{5}\) \(b=\sqrt[4]{5}\) \(c=\sqrt[3]{10}\) \(d=\sqrt[4]{10}\)

Hints

- For the same radicand greater than \(1\), compare the radical indices. - For the same index, compare the radicands. - Use a common index to compare \(a\) and \(d\).

Solution

1. With the same base greater than \(1\), a larger radical index gives a smaller value. Thus \(b<a\) and \(d<c\). 2. With the same radical index, the larger radicand gives the larger value. Thus \(b<d\) and \(a<c\). 3. Compare \(a\) and \(d\) using index \(12\): \(a=\sqrt[12]{625}\) and \(d=\sqrt[12]{1000}\). Since \(625<1000\), \(a<d\). 4. Therefore, \(b<a<d<c\). Numerically, \(b\approx1.50\), \(a\approx1.71\), \(d\approx1.78\), and \(c\approx2.15\).

Answer

\(b<a<d<c\), with approximate values \(1.50<1.71<1.78<2.15\)
5149529
Simplify each expression using exponent properties before evaluating it. a) \(\frac{\sqrt[3]{2^7}}{\sqrt[3]{2}}\) b) \(\sqrt{\sqrt[3]{729}}\) c) \((8\cdot27)^{\frac13}\) d) \(0.5^{-2}\sqrt[4]{16}\)

Hints

- Combine radicals with matching indices in a quotient or product. - A root of a root multiplies the radical indices. - Rewrite the decimal as a fraction before applying the negative exponent.

Solution

1. \(\frac{\sqrt[3]{2^7}}{\sqrt[3]{2}}=\sqrt[3]{2^6}=2^2=4\). 2. \(\sqrt{\sqrt[3]{729}}=\sqrt[6]{729}=3\), because \(3^6=729\). 3. \((8\cdot27)^{\frac13}=8^{\frac13}27^{\frac13}=2\cdot3=6\). 4. \(0.5^{-2}=(\frac12)^{-2}=4\), and \(\sqrt[4]{16}=2\). The product is \(8\).

Answer

a) \(4\) b) \(3\) c) \(6\) d) \(8\)
5149549
Order the expressions from least to greatest. Justify the order by rewriting each expression in the form \(2^n\). \(T_1=\sqrt[4]{4}\) \(T_2=0.5^{-1}\) \(T_3=\frac1{\sqrt2}\) \(T_4=4^{\frac13}\)

Hints

- Use \(2\) as the common base. - Rewrite radicals and reciprocals as exponents. - For a base greater than \(1\), larger exponents give larger values.

Solution

1. \(T_1=\sqrt[4]{2^2}=2^{\frac12}\). 2. \(T_2=\left(\frac12\right)^{-1}=2^1\). 3. \(T_3=2^{-\frac12}\). 4. \(T_4=(2^2)^{\frac13}=2^{\frac23}\). 5. Since \(-\frac12<\frac12<\frac23<1\), the order is \(T_3<T_1<T_4<T_2\).

Answer

\(T_3<T_1<T_4<T_2\)
5149559
Simplify for \(x>0\) and write the result as a power with a rational exponent. \(\frac{\sqrt[3]{x^2}\sqrt x}{x}\) Then verify your result for \(x=64\) by evaluating both the original and simplified expressions.

Hints

- Rewrite every factor as a power of \(x\). - Add numerator exponents and subtract the denominator exponent. - Use a common denominator for the exponent fractions.

Solution

1. Rewrite the radicals: \(\sqrt[3]{x^2}=x^{\frac23}\) and \(\sqrt x=x^{\frac12}\). 2. Combine exponents: \(x^{\frac23+\frac12-1}=x^{\frac46+\frac36-\frac66}=x^{\frac16}\). 3. For \(x=64\), the original expression is \(\frac{16\cdot8}{64}=2\), and the simplified expression is \(64^{\frac16}=2\).

Answer

The simplified expression is \(x^{\frac16}\). For \(x=64\), both forms equal \(2\).
5149579
Find the missing value in each equation. In part a), \(x\) is a natural number and \(x\ge2\). a) \(\sqrt[x]{2^{15}}=8\) b) \(\frac{\sqrt[3]{7^5}}{7^k}=\sqrt[3]{7^2}\) c) \(10^k=\frac1{\sqrt[4]{100}}\)

Hints

- Rewrite both sides of each equation with the same base. - A reciprocal can be written using a negative exponent. - When equal powers have the same positive base other than \(1\), their exponents are equal.

Solution

1. For a), rewrite both sides with base \(2\): \(2^{\frac{15}{x}}=2^3\). Thus \(\frac{15}{x}=3\), so \(x=5\). 2. For b), \(\frac{7^{\frac53}}{7^k}=7^{\frac53-k}=7^{\frac23}\). Therefore \(\frac53-k=\frac23\), so \(k=1\). 3. For c), \(\frac1{\sqrt[4]{100}}=\frac1{(10^2)^{\frac14}}=10^{-\frac12}\). Therefore \(k=-\frac12\).

Answer

a) \(x=5\) b) \(k=1\) c) \(k=-\frac12\)
5149619
Use exponent properties to simplify each expression. Write each result without a radical. Assume all variables are positive, \(a>b\), and \(n\) is a natural number with \(n\ge2\). a) \(\sqrt[3]{\frac{27}{x^{-6}}}\) b) \(\frac1{\sqrt[n]{a^{3n}b^{2n}}}\) c) \(\frac{\sqrt[3]{x^2}\sqrt[3]{x^7}}{x^2}\) d) \(\sqrt[4]{(a-b)^{12}}\)

Hints

- Rewrite negative exponents as reciprocals, or reciprocals as negative exponents. - Combine factors with the same base before simplifying. - Treat a parenthesized expression as one base. - Reduce exponents that contain the variable \(n\).

Solution

1. Since \(\frac1{x^{-6}}=x^6\), \(\sqrt[3]{\frac{27}{x^{-6}}}=\sqrt[3]{3^3x^6}=3x^2\). 2. \(\sqrt[n]{a^{3n}b^{2n}}=a^3b^2\), so \(\frac1{\sqrt[n]{a^{3n}b^{2n}}}=a^{-3}b^{-2}\). 3. \(\frac{\sqrt[3]{x^2}\sqrt[3]{x^7}}{x^2}=\frac{\sqrt[3]{x^9}}{x^2}=\frac{x^3}{x^2}=x\). 4. Because \(a-b>0\), \(\sqrt[4]{(a-b)^{12}}=(a-b)^{\frac{12}{4}}=(a-b)^3\).

Answer

a) \(3x^2\) b) \(a^{-3}b^{-2}\) c) \(x\) d) \((a-b)^3\)
5149639
Use exponent properties to simplify each expression completely. Assume all variables are positive. a) \(\left(z^{\frac23}\right)^{-\frac32}\) b) \(\frac{\sqrt{x}\sqrt[3]{x}}{\sqrt[6]{x^5}}\) c) \((27a^6)^{\frac13}\)

Hints

- Multiply the exponents in a power raised to another power. - Rewrite every radical as a rational exponent. - Recall the value of a nonzero number raised to the zero power. - Identify the cube root of \(27\).

Solution

1. \(\left(z^{\frac23}\right)^{-\frac32}=z^{\frac23\cdot\left(-\frac32\right)}=z^{-1}=\frac1z\). 2. \(\frac{\sqrt{x}\sqrt[3]{x}}{\sqrt[6]{x^5}}=x^{\frac12+\frac13-\frac56}=x^{\frac36+\frac26-\frac56}=x^0=1\). 3. \((27a^6)^{\frac13}=27^{\frac13}a^{\frac63}=3a^2\).

Answer

a) \(\frac1z\) b) \(1\) c) \(3a^2\)
5149649
Use exponent properties to simplify each expression completely. Assume \(a>0\), \(x>0\), and \(z>0\). a) \(\sqrt{a\sqrt[3]{a}}\) b) \(\frac{(8x^3)^{\frac23}}{4x}\) c) \(\frac{z^{-\frac12}\sqrt[4]{z^6}}{z}\)

Hints

- For nested radicals, simplify from the inside out. - Rewrite \(8\) as a power that works well with an exponent of \(\frac23\). - A variable in the denominator has an exponent of \(-1\) when moved to the numerator. - Express every factor with the same base before combining exponents.

Solution

1. \(\sqrt{a\sqrt[3]{a}}=\left(a^1a^{\frac13}\right)^{\frac12}=\left(a^{\frac43}\right)^{\frac12}=a^{\frac23}\). 2. \((8x^3)^{\frac23}=8^{\frac23}x^2=4x^2\), so \(\frac{(8x^3)^{\frac23}}{4x}=\frac{4x^2}{4x}=x\). 3. \(\frac{z^{-\frac12}\sqrt[4]{z^6}}{z}=z^{-\frac12+\frac64-1}=z^{-\frac24+\frac64-\frac44}=z^0=1\).

Answer

a) \(a^{\frac23}\) b) \(x\) c) \(1\)
5149759
Use exponent and radical properties to simplify each expression completely. Assume all variables are positive. a) \(\sqrt{x\sqrt{x}}\) b) \(\left(y^{\frac13}+y^{-\frac13}\right)^2\) c) \(\frac{\sqrt[3]{z^4}z^{-1}}{\sqrt[6]{z}}\)

Hints

- Rewrite nested radicals as powers and multiply the exponents. - Expand the square of a binomial carefully. - Opposite exponents add to zero when their powers are multiplied. - Express all factors in part c) as powers of \(z\).

Solution

1. \(\sqrt{x\sqrt{x}}=\left(x\cdot x^{\frac12}\right)^{\frac12}=\left(x^{\frac32}\right)^{\frac12}=x^{\frac34}\). 2. \(\left(y^{\frac13}+y^{-\frac13}\right)^2=y^{\frac23}+2y^{\frac13}y^{-\frac13}+y^{-\frac23}=y^{\frac23}+2+y^{-\frac23}\). 3. \(\frac{\sqrt[3]{z^4}z^{-1}}{\sqrt[6]{z}}=z^{\frac43-1-\frac16}=z^{\frac86-\frac66-\frac16}=z^{\frac16}\).

Answer

a) \(x^{\frac34}\) b) \(y^{\frac23}+2+y^{-\frac23}\) c) \(z^{\frac16}\)
5149769
Simplify each expression completely. Assume all variables are positive. a) \((2\sqrt a+3\sqrt b)^2\) b) \(\sqrt[4]{x^3}\sqrt[8]{x^2}\) c) \(\frac{y^2\sqrt y}{\sqrt[3]{y^2}}\)

Hints

- When squaring a binomial, include the middle product and square each coefficient. - Rewrite radicals as rational exponents. - Use a common denominator when adding and subtracting exponent fractions.

Solution

1. Expand the binomial: \((2\sqrt a+3\sqrt b)^2=(2\sqrt a)^2+2(2\sqrt a)(3\sqrt b)+(3\sqrt b)^2=4a+12\sqrt{ab}+9b\). 2. \(\sqrt[4]{x^3}\sqrt[8]{x^2}=x^{\frac34}x^{\frac28}=x^{\frac34+\frac14}=x\). 3. \(\frac{y^2\sqrt y}{\sqrt[3]{y^2}}=y^{2+\frac12-\frac23}=y^{\frac{12}{6}+\frac36-\frac46}=y^{\frac{11}{6}}\).

Answer

a) \(4a+12\sqrt{ab}+9b\) b) \(x\) c) \(y^{\frac{11}{6}}\)
5149789
For \(a>0\), write the expression as a single power of \(a\): \(\sqrt[3]{a\sqrt[3]{a^2}}\)

Hints

- Work from the inner radical outward. - Write \(a\) as \(a^1\). - Multiply exponents when raising a power to another power.

Solution

1. Rewrite the inner radical: \(\sqrt[3]{a^2}=a^{\frac23}\). 2. Combine the factors inside the outer radical: \(a\cdot a^{\frac23}=a^{\frac53}\). 3. Apply the outer cube root: \(\left(a^{\frac53}\right)^{\frac13}=a^{\frac59}\).

Answer

\(a^{\frac59}\)
5149799
For \(x>0\) and \(y>0\), simplify the expression completely: \(\frac{\sqrt[3]{x^2y}}{\sqrt{xy^{-1}}}\)

Hints

- Rewrite both radicals using rational exponents. - Subtract denominator exponents from numerator exponents. - Be careful when subtracting a negative exponent.

Solution

1. Rewrite the radicals: \(\sqrt[3]{x^2y}=x^{\frac23}y^{\frac13}\) and \(\sqrt{xy^{-1}}=x^{\frac12}y^{-\frac12}\). 2. Subtract exponents for each base: \(x^{\frac23-\frac12}y^{\frac13-(-\frac12)}\). 3. Simplify the exponents: \(\frac23-\frac12=\frac16\) and \(\frac13+\frac12=\frac56\). 4. The expression is \(x^{\frac16}y^{\frac56}\).

Answer

\(x^{\frac16}y^{\frac56}\)
5149809
A cube with edge length \(a\) has surface area \(S=6a^2\) and volume \(V=a^3\). Derive a formula for \(V\) in terms of \(S\). Write your result in the form \(V=\left(\frac{S}{k}\right)^n\) and identify \(k\) and \(n\).

Hints

- Solve the surface-area formula for the common variable \(a\). - Substitute that expression into the volume formula. - Rewrite the square root as a rational exponent. - Multiply exponents when raising a power to another power.

Solution

1. Solve the surface-area formula for \(a\): \(S=6a^2\), so \(a=\sqrt{\frac S6}\). 2. Substitute into the volume formula: \(V=\left(\sqrt{\frac S6}\right)^3\). 3. Rewrite the square root as a rational exponent: \(V=\left(\left(\frac S6\right)^{\frac12}\right)^3=\left(\frac S6\right)^{\frac32}\). 4. Therefore \(k=6\) and \(n=\frac32\).

Answer

\(V=\left(\frac S6\right)^{\frac32}\), so \(k=6\) and \(n=\frac32\).
5149819
A manufacturer makes cube-shaped storage tanks. A new tank must have eight times the volume of the current model. The surface area of a cube in terms of its volume is \(S=6V^{\frac23}\). By what factor will the material needed for the tank's outer surface increase? Justify your answer using exponent properties.

Hints

- Replace \(V\) in the formula with eight times the original volume. - Distribute the exponent over the product. - Interpret \(8^{\frac23}\) using a cube root and a square. - Compare the new expression with the original surface-area expression.

Solution

1. Let the original volume be \(V_1\), so \(S_1=6V_1^{\frac23}\). 2. The new volume is \(V_2=8V_1\). Therefore \(S_2=6(8V_1)^{\frac23}\). 3. Apply the power-of-a-product property: \(S_2=6\cdot8^{\frac23}V_1^{\frac23}\). 4. Since \(8^{\frac23}=(\sqrt[3]{8})^2=2^2=4\), \(S_2=4(6V_1^{\frac23})=4S_1\).

Answer

The surface area, and therefore the material needed, increases by a factor of \(4\).
5149939
Decide whether each statement is true or false. Justify each conclusion with general reasoning or a counterexample. a) “If the exponent \(n\) in a power with positive base \(a\) is doubled, the value of the power also doubles.” b) “For every positive number \(a\) and every rational exponent \(x\) with \(0<x<1\), the value \(a^x\) is less than \(a\).”

Hints

- Test each claim with simple numerical examples. - Consider a base between \(0\) and \(1\). - Interpret an exponent such as \(\frac12\) as a root. - A single valid counterexample disproves a universal statement.

Solution

1. Statement a) is false. For example, with \(a=3\) and \(n=1\), \(3^1=3\), but doubling the exponent gives \(3^2=9\), not \(6\). 2. Statement b) is false. It is true when \(a>1\), but not when \(0<a<1\). For example, \(0.25^{\frac12}=0.5\), and \(0.5>0.25\).

Answer

a) False. For example, \(3^1=3\), but \(3^2=9\), not \(6\). b) False. For example, \(0.25^{\frac12}=0.5>0.25\).
5149969
A designer creates cube-shaped stools. The volume of a cube is \(V=a^3\). a) By what factor must the edge length be multiplied so that the new stool has one-eighth of the original volume? b) A model must have exactly twice the volume of a cube with edge length \(a\). Find the exact factor by which the original edge length must be multiplied. c) If a cube's volume is reduced by \(50\%\), what factor of the original edge length remains? Write the factor using a radical.

Hints

- Which operation reverses raising a length to the third power? - A cube root can also be written using an exponent of \(\frac{1}{3}\). - Represent the new edge length as \(ka\). - Translate each volume change into an equation involving \((ka)^3\).

Solution

1. For part a), let the new edge length be \(ka\). Then \((ka)^3=\frac{1}{8}a^3\), so \(k^3=\frac{1}{8}\) and \(k=\frac{1}{2}\). 2. For part b), \((ka)^3=2a^3\), so \(k^3=2\) and \(k=\sqrt[3]{2}=2^{1/3}\). 3. For part c), a \(50\%\) reduction leaves one-half of the volume. Thus, \((ka)^3=\frac{1}{2}a^3\), so \(k=\sqrt[3]{\frac{1}{2}}=\left(\frac{1}{2}\right)^{1/3}=2^{-1/3}\).

Answer

a) \(\frac{1}{2}\) b) \(\sqrt[3]{2}=2^{1/3}\) c) \(\sqrt[3]{\frac{1}{2}}\), equivalently \(2^{-1/3}\)
5149979
The area of a square plate is \(A=s^2\), where \(s\) is the side length. a) Show algebraically how the side length must change to double the area. b) The side length is reduced by \(20\%\). What percent of the original area is lost?

Hints

- Use the relationship between a square's area and its side length. - A square root can also be written using an exponent of \(\frac{1}{2}\). - What decimal factor remains after a \(20\%\) decrease? - When a product is squared, each factor is squared.

Solution

1. Let the original area be \(A_1=s_1^2\) and the new area be \(A_2=2A_1\). Since \(A_2=s_2^2\), \(s_2^2=2s_1^2\). 2. Taking the positive square root gives \(s_2=\sqrt{2}s_1=2^{1/2}s_1\). The side length must be multiplied by \(\sqrt{2}\), or equivalently \(2^{1/2}\). 3. A \(20\%\) reduction in side length gives \(s_{\text{new}}=0.8s_{\text{old}}\). 4. Then \(A_{\text{new}}=(0.8s_{\text{old}})^2=0.64A_{\text{old}}\). The area lost is \(100\%-64\%=36\%\).

Answer

a) Multiply the side length by \(\sqrt{2}=2^{1/2}\). b) \(36\%\) of the original area is lost.
5152879
Use properties of negative and rational exponents to simplify. Assume \(x\ne0\), \(z>0\), and \(b\ne0\). a) \(x^{-3}(x^5-2x^3+4x^2)\) b) \(z^{\frac12}(z^{\frac32}-5z^{-\frac12})\) c) \(2a^2b^{-2}(ab^2-3b^3)\)

Hints

- Distribute the factor outside each set of parentheses. - Add exponents when multiplying powers with the same base. - Recall that a nonzero number raised to the zero power equals \(1\). - Rewrite a negative exponent as a reciprocal when useful.

Solution

1. Distribute and add exponents on like bases. 2. \(x^{-3}(x^5-2x^3+4x^2)=x^2-2x^0+4x^{-1}=x^2-2+\frac4x\). 3. \(z^{\frac12}(z^{\frac32}-5z^{-\frac12})=z^2-5z^0=z^2-5\). 4. \(2a^2b^{-2}(ab^2-3b^3)=2a^3b^0-6a^2b=2a^3-6a^2b\).

Answer

a) \(x^2-2+\frac4x\) b) \(z^2-5\) c) \(2a^3-6a^2b\)
5152889
Simplify each expression completely. Assume \(x\ne0\), \(y\ne0\), \(a>0\), \(u\ne0\), and \(v\ne0\). a) \((xy^2)^3(x^{-2}y^{-4}+3x^{-3}y^{-6})\) b) \(\sqrt a\left(2\sqrt{a^3}-\frac4{\sqrt a}+a^{-\frac12}\right)\) c) \(\frac23u^2v\left(6u^{-2}-9v^{-1}+\frac32uv^2\right)\)

Hints

- Apply the power-of-a-product property before distributing in part a). - Rewrite radicals as rational exponents. - Add exponents on like bases after multiplying. - Multiply numerical coefficients separately from variable factors.

Solution

1. \((xy^2)^3=x^3y^6\). Distribute: \(x^3y^6(x^{-2}y^{-4}+3x^{-3}y^{-6})=xy^2+3\). 2. Rewrite the radicals as powers and distribute: \(a^{\frac12}(2a^{\frac32}-4a^{-\frac12}+a^{-\frac12})=2a^2-4+1=2a^2-3\). 3. Distribute the coefficient and variables: \(\frac23u^2v\left(6u^{-2}-9v^{-1}+\frac32uv^2\right)=4v-6u^2+u^3v^3\).

Answer

a) \(xy^2+3\) b) \(2a^2-3\) c) \(4v-6u^2+u^3v^3\)
5154139
Write or simplify each expression as directed. Assume all variables are positive. a) Write \(x^{1.25}\) as a radical with integer exponents. b) Simplify \(\sqrt[3]{a^2}\cdot a^{\frac13}\). c) Evaluate \(16^{-0.25}\) without a calculator. d) Simplify \(\frac{\sqrt{z^3}}{\sqrt[4]{z^2}}\).

Hints

- Rewrite decimal exponents as fractions. - Add or subtract exponents when the bases are the same. - A negative exponent represents a reciprocal. - Rewrite radicals as rational exponents.

Solution

1. Since \(1.25=\frac54\), \(x^{1.25}=x^{\frac54}=\sqrt[4]{x^5}\). 2. \(\sqrt[3]{a^2}\cdot a^{\frac13}=a^{\frac23}a^{\frac13}=a\). 3. Since \(-0.25=-\frac14\), \(16^{-0.25}=16^{-\frac14}=\frac1{\sqrt[4]{16}}=\frac12\). 4. \(\frac{\sqrt{z^3}}{\sqrt[4]{z^2}}=z^{\frac32-\frac24}=z^{\frac32-\frac12}=z\).

Answer

a) \(\sqrt[4]{x^5}\) b) \(a\) c) \(\frac12\) d) \(z\)
5154149
Assume \(x>0\) and \(y>0\). a) Write \(\sqrt{x\sqrt{x}}\) as a single power of \(x\). b) Simplify \(\sqrt[6]{y^4\sqrt[3]{y^6}}\). c) Find \(k\) if \(\sqrt[3]{5^k}=25\).

Hints

- Work from the inner radical outward. - Simplify the expression inside the sixth root first. - Rewrite both sides of the equation with the same base. - Relate the radical index to the denominator of a rational exponent.

Solution

1. \(\sqrt{x\sqrt{x}}=\left(x\cdot x^{\frac12}\right)^{\frac12}=\left(x^{\frac32}\right)^{\frac12}=x^{\frac34}\). 2. First, \(\sqrt[3]{y^6}=y^2\). Then \(\sqrt[6]{y^4\sqrt[3]{y^6}}=\sqrt[6]{y^6}=y\). 3. Rewrite both sides with base \(5\): \(5^{\frac{k}{3}}=5^2\). Thus \(\frac{k}{3}=2\), so \(k=6\).

Answer

a) \(x^{\frac34}\) b) \(y\) c) \(k=6\)
5154369
The mass \(m\), in kilograms, of glass needed for a container with interior volume \(V\), in liters, is modeled by \(m=0.4V^{\frac23}\). a) Find the mass needed for a container with volume \(125\,\text{L}\). b) Solve the formula for \(V\) in terms of \(m\). c) Find the interior volume of a container that uses exactly \(10\,\text{kg}\) of glass.

Hints

- Interpret an exponent of \(\frac23\) using a cube root and a square. - Isolate the power of \(V\) before undoing its exponent. - Use the reciprocal exponent to solve for the base. - Check part c) against the result in part a).

Solution

1. Substitute \(V=125\): \(m=0.4\cdot125^{\frac23}\). 2. Since \(125^{\frac23}=(\sqrt[3]{125})^2=25\), \(m=0.4\cdot25=10\). Thus the mass is \(10\,\text{kg}\). 3. Solve for \(V\): \(\frac{m}{0.4}=V^{\frac23}\), so \(2.5m=V^{\frac23}\). Raise both sides to the \(\frac32\) power: \(V=(2.5m)^{\frac32}\). 4. For \(m=10\), \(V=(2.5\cdot10)^{\frac32}=25^{\frac32}=125\). Thus the volume is \(125\,\text{L}\).

Answer

a) \(10\,\text{kg}\) b) \(V=(2.5m)^{\frac32}\) c) \(125\,\text{L}\)
5154379
For \(x\ge0\), the variables \(x\) and \(y\) are related by \(y=3x^{0.75}\). a) Find \(y\) when \(x=16\). b) Solve the equation for \(x\) in terms of \(y\). c) Determine how \(y\) changes when \(x\) is multiplied by \(81\). Justify your answer using exponent properties.

Hints

- Rewrite the decimal exponent as a fraction. - To solve for the base, raise both sides to the reciprocal exponent. - Distribute a power over a product. - Evaluate \(81^{\frac34}\) using a fourth root and a cube.

Solution

1. Since \(0.75=\frac34\), when \(x=16\), \(y=3\cdot16^{\frac34}=3\cdot8=24\). 2. Divide by \(3\): \(\frac y3=x^{\frac34}\). Raise both sides to the \(\frac43\) power: \(x=\left(\frac y3\right)^{\frac43}\). 3. If \(x\) is replaced by \(81x\), then \(y_{\text{new}}=3(81x)^{\frac34}=3\cdot81^{\frac34}x^{\frac34}\). 4. Since \(81^{\frac34}=(\sqrt[4]{81})^3=27\), \(y_{\text{new}}=27y\).

Answer

a) \(y=24\) b) \(x=\left(\frac y3\right)^{\frac43}\) c) \(y\) is multiplied by \(27\).
5155879
Simplify each expression completely. Write the final result as a power with a rational exponent. Assume all variables are positive. a) \(\sqrt{x}\cdot x^2\) b) \(\frac{\sqrt[3]{y^2}}{y}\) c) \(\left(a^{0.5}a^{\frac14}\right)^2\) d) \(\frac{z^{1.5}}{\sqrt{z^3}}\)

Hints

- Rewrite each radical as a rational exponent. - Add exponents when multiplying like bases and subtract when dividing. - Multiply exponents when raising a power to another power.

Solution

1. \(\sqrt{x}\cdot x^2=x^{\frac12+2}=x^{\frac52}\). 2. \(\frac{\sqrt[3]{y^2}}{y}=y^{\frac23-1}=y^{-\frac13}\). 3. \(\left(a^{0.5}a^{\frac14}\right)^2=\left(a^{\frac12+\frac14}\right)^2=\left(a^{\frac34}\right)^2=a^{\frac32}\). 4. \(\frac{z^{1.5}}{\sqrt{z^3}}=\frac{z^{\frac32}}{z^{\frac32}}=z^0=1\).

Answer

a) \(x^{\frac52}\) b) \(y^{-\frac13}\) c) \(a^{\frac32}\) d) \(z^0=1\)
5246269
Determine whether each statement is true or false. Briefly justify your answer. 1. The equation \(\sqrt[3]{x}=-5\) has the solution \(x=-125\). 2. There is a real number \(a\) for which \(\sqrt[4]{a}=-2\). 3. The expression \(\sqrt[5]{-1}\) is undefined because roots of negative numbers do not exist.

Hints

- Compare even and odd radical indices. - Check a proposed root by raising it to the radical index. - A principal even root is nonnegative.

Solution

1. True, because \((-5)^3=-125\). 2. False, because a principal even root is never negative. 3. False, because odd roots of negative numbers are defined. In fact, \(\sqrt[5]{-1}=-1\).

Answer

1. True 2. False 3. False
5246429
A square lot has area \(A=2^8\cdot5^2\,\text{m}^2\). a) Use exponent properties to find the side length \(s\) as a whole number. b) A cube-shaped building is constructed so that its square base exactly covers the lot. Find the building's volume \(V\). c) Write \(V\) as a product of powers with bases \(2\) and \(5\).

Hints

- Apply the square root to each factor by multiplying its exponent by \(\frac12\). - Use the volume formula for a cube. - Apply the power-of-a-product and power-of-a-power properties.

Solution

1. \(s=\sqrt{2^8\cdot5^2}=2^4\cdot5=80\,\text{m}\). 2. The cube has edge length \(80\,\text{m}\), so \(V=80^3=512{,}000\,\text{m}^3\). 3. Since \(80=2^4\cdot5\), \(V=(2^4\cdot5)^3=2^{12}\cdot5^3\).

Answer

a) \(s=80\,\text{m}\) b) \(V=512{,}000\,\text{m}^3\) c) \(V=2^{12}\cdot5^3\)
5246529
Evaluate each expression over the real numbers. Write “undefined” if it has no real value. a) \(\sqrt[3]{-125}+\sqrt[4]{16}\) b) \(5\sqrt[6]{-64}\) c) \(\sqrt[5]{-1}-\sqrt[3]{-1}\) d) \(\frac{\sqrt[4]{0.0001}}{\sqrt[3]{-0.001}}\)

Hints

- Evaluate each radical before combining the terms. - Even roots of negative numbers are not real. - Odd roots preserve the sign of the radicand.

Solution

a) \(\sqrt[3]{-125}+\sqrt[4]{16}=-5+2=-3\). b) \(\sqrt[6]{-64}\) has no real value, so the expression is undefined over the real numbers. c) \(\sqrt[5]{-1}-\sqrt[3]{-1}=-1-(-1)=0\). d) \(\sqrt[4]{0.0001}=0.1\) and \(\sqrt[3]{-0.001}=-0.1\), so the quotient is \(\frac{0.1}{-0.1}=-1\).

Answer

a) \(-3\) b) Undefined c) \(0\) d) \(-1\)
5246589
Let \(f(x)=\sqrt[4]{x-3}\) and \(g(x)=\sqrt[3]{x-3}\). a) Find the maximal real domain of each function. b) Explain why the domains are different. c) Find all real values of \(x\) for which \(f(x)=g(x)\).

Hints

- Compare the domain restrictions for even-index and odd-index radicals. - In part c, substitute a new variable for \(x-3\). - Remember to consider zero separately before dividing by a power of the new variable.

Solution

1. For \(f\), the fourth root requires \(x-3\geq0\), so \(x\geq3\). Thus the domain of \(f\) is \([3,\infty)\). 2. A cube root is defined for every real radicand, so the domain of \(g\) is \((-\infty, \infty)\). 3. Even-index roots require nonnegative radicands because even powers cannot be negative over the real numbers. Odd-index roots accept every real radicand. 4. To solve \(\sqrt[4]{x-3}=\sqrt[3]{x-3}\), first require \(x\geq3\). Let \(u=x-3\), so \(u\geq0\). Then \(u^{\frac14}=u^{\frac13}\). 5. If \(u=0\), then \(x=3\). If \(u>0\), divide by \(u^{\frac14}\) to get \(u^{\frac1{12}}=1\), so \(u=1\) and \(x=4\). Both values check in the original equation.

Answer

a) \(D_f=[3,\infty)\); \(D_g=(-\infty, \infty)\) b) An even-index root requires a nonnegative radicand, while an odd-index root is defined for every real radicand. c) \(x=3\) or \(x=4\)
5246669
Simplify each radical expression under the given condition. a) \(\sqrt[4]{(x-y)^4}\) when \(x<y\) b) Evaluate \(\sqrt[6]{(a-b)^{12}}\) when \(a=3\) and \(b=5\). Does the value change when the values are switched, so \(a=5\) and \(b=3\)? c) \(\sqrt{(z-10)^6}\) when \(z<10\)

Hints

- An even-index radical of an even power may produce an absolute value. - Use the given inequality to determine the sign of the expression inside the absolute value. - Compare \((a-b)^2\) and \((b-a)^2\).

Solution

1. \(\sqrt[4]{(x-y)^4}=|x-y|\). Since \(x<y\), \(x-y<0\), so \(|x-y|=y-x\). 2. \(\sqrt[6]{(a-b)^{12}}=(a-b)^2\). For \(a=3\) and \(b=5\), the value is \((3-5)^2=4\). After switching the values, the result is \((5-3)^2=4\), so it does not change. 3. \(\sqrt{(z-10)^6}=|(z-10)^3|\). Since \(z<10\), \(z-10<0\), so \((z-10)^3<0\). Therefore the expression simplifies to \(-(z-10)^3=(10-z)^3\).

Answer

a) \(y-x\) b) \(4\); the value does not change. c) \((10-z)^3\)
5246759
Simplify each expression without a calculator. 1) \(\sqrt{(-13)^2}\) 2) \(\sqrt[4]{(-3)^4}\) 3) \(\sqrt{(4-\sqrt{17})^2}\) 4) \(\sqrt[6]{(2-\sqrt{3})^6}\)

Hints

- For an even index, \(\sqrt[n]{u^n}=|u|\). - Determine the sign of each expression inside an absolute value. - Compare radicals by comparing their nonnegative radicands.

Solution

1. \(\sqrt{(-13)^2}=|-13|=13\). 2. \(\sqrt[4]{(-3)^4}=|-3|=3\). 3. \(\sqrt{(4-\sqrt{17})^2}=|4-\sqrt{17}|\). Since \(4=\sqrt{16}<\sqrt{17}\), the expression inside the absolute value is negative. The result is \(\sqrt{17}-4\). 4. \(\sqrt[6]{(2-\sqrt{3})^6}=|2-\sqrt{3}|\). Since \(2=\sqrt4>\sqrt3\), the expression inside the absolute value is positive. The result is \(2-\sqrt3\).

Answer

1) \(13\) 2) \(3\) 3) \(\sqrt{17}-4\) 4) \(2-\sqrt3\)
5246769
Find the exact value of each expression or solve the equation. a) \(\sqrt[3]{(-5)^3}+\sqrt{(-5)^2}\) b) \(\sqrt[4]{(\sqrt5-3)^4}\) c) \(\sqrt{(3-\pi)^2}\) d) For which real numbers \(x\) is \(\sqrt[8]{x^8}=-x\)?

Hints

- For an odd index, \(\sqrt[n]{u^n}=u\); for an even index, the result is \(|u|\). - Determine whether \(\sqrt5-3\) and \(3-\pi\) are positive or negative. - Ask when a number’s absolute value equals its opposite.

Solution

1. \(\sqrt[3]{(-5)^3}=-5\) and \(\sqrt{(-5)^2}=|-5|=5\), so the sum is \(0\). 2. \(\sqrt[4]{(\sqrt5-3)^4}=|\sqrt5-3|\). Since \(\sqrt5<3\), the result is \(3-\sqrt5\). 3. \(\sqrt{(3-\pi)^2}=|3-\pi|\). Since \(\pi>3\), the result is \(\pi-3\). 4. The equation is equivalent to \(|x|=-x\). This is true exactly when \(x\leq0\).

Answer

a) \(0\) b) \(3-\sqrt5\) c) \(\pi-3\) d) \(x\leq0\)
5247369
For \(y\ge0\), let \(A=\sqrt[6]{y^3}\), \(B=\sqrt[4]{y^2}\), and \(C=\sqrt[10]{y^5}\). Explain why the three expressions have the same value for every allowed value of \(y\). Write their common value in simplest form.

Hints

- Rewrite each radical as a power with a fractional exponent. - Reduce each exponent fraction. - Compare the reduced exponents.

Solution

1. Rewrite each radical as a rational exponent. 2. \(A=y^{\frac36}=y^{\frac12}\). 3. \(B=y^{\frac24}=y^{\frac12}\). 4. \(C=y^{\frac5{10}}=y^{\frac12}\). 5. All three exponent fractions reduce to \(\frac12\), so the expressions are equivalent and equal \(\sqrt y\).

Answer

\(A=B=C=y^{\frac12}=\sqrt y\).
5247399
Determine which number is greater: \(a=\sqrt[3]{30}\) or \(b=\sqrt[4]{90}\). For each number, give an interval of length \(0.1\) that contains it, and use the intervals to justify your comparison.

Hints

- First compare each radicand with nearby integer powers. - Test tenths between \(3\) and \(4\). - Look for one benchmark value that lies between the two numbers.

Solution

1. Since \(3^3=27\) and \(4^3=64\), \(a\) is between \(3\) and \(4\). More precisely, \((3.1)^3=29.791\) and \((3.2)^3=32.768\), so \(3.1<a<3.2\). 2. Since \(3^4=81\) and \(4^4=256\), \(b\) is between \(3\) and \(4\). More precisely, \((3.0)^4=81\) and \((3.1)^4=92.3521\), so \(3.0<b<3.1\). 3. Because \(a>3.1\) and \(b<3.1\), it follows that \(a>b\).

Answer

\(3.1<a<3.2\) and \(3.0<b<3.1\), so \(a>b\).
5247459
Simplify each expression by reducing the radical index and the exponent as far as possible. Pay attention to the sign of each difference. a) \(\sqrt[4]{(3-\sqrt{11})^2}\) b) \(\sqrt[6]{(\sqrt2-\sqrt7)^2}\) c) \(\sqrt[10]{(4-\sqrt{17})^2}\)

Hints

- Reducing an even radical index and an even exponent may introduce an absolute value. - Compare the terms in each difference before removing the absolute value. - You can compare square roots by comparing their nonnegative radicands.

Solution

1. \(\sqrt[4]{(3-\sqrt{11})^2}=\sqrt{|3-\sqrt{11}|}\). Since \(3=\sqrt9<\sqrt{11}\), the difference is negative, so the result is \(\sqrt{\sqrt{11}-3}\). 2. \(\sqrt[6]{(\sqrt2-\sqrt7)^2}=\sqrt[3]{|\sqrt2-\sqrt7|}\). Since \(\sqrt2<\sqrt7\), the difference is negative, so the result is \(\sqrt[3]{\sqrt7-\sqrt2}\). 3. \(\sqrt[10]{(4-\sqrt{17})^2}=\sqrt[5]{|4-\sqrt{17}|}\). Since \(4=\sqrt{16}<\sqrt{17}\), the difference is negative, so the result is \(\sqrt[5]{\sqrt{17}-4}\).

Answer

a) \(\sqrt{\sqrt{11}-3}\) b) \(\sqrt[3]{\sqrt7-\sqrt2}\) c) \(\sqrt[5]{\sqrt{17}-4}\)
5247469
Let \(T(x)=\sqrt[4]{(x-5)^2}\). a) Evaluate \(T(1)\). b) A student claims, “You can simplify the expression to \(\sqrt{x-5}\).” Use your result from part a to explain why this claim is incorrect when \(x=1\). c) Give a simplified form of \(T(x)\) that is valid for every \(x<5\) and contains no absolute value symbols.

Hints

- Evaluate the original expression before judging the proposed simplification. - Compare the real domains of the original and proposed expressions. - For \(x<5\), determine the sign of \(x-5\) before removing an absolute value.

Solution

1. \(T(1)=\sqrt[4]{(1-5)^2}=\sqrt[4]{16}=2\). 2. The proposed expression gives \(\sqrt{1-5}=\sqrt{-4}\), which is not a real number, while the original expression equals \(2\). Therefore the proposed simplification is not equivalent to the original expression. 3. In general, \(\sqrt[4]{(x-5)^2}=\sqrt{|x-5|}\). When \(x<5\), \(x-5<0\), so \(|x-5|=5-x\). Thus \(T(x)=\sqrt{5-x}\).

Answer

a) \(2\) b) At \(x=1\), the original expression equals \(2\), but \(\sqrt{x-5}=\sqrt{-4}\) is not real. c) \(\sqrt{5-x}\)
5247489
A student claims, “\(\sqrt[n]{a^n}=a\) always, because the power and the root cancel.” a) Test the claim for the even index \(n=4\) using \(a=-3\). b) Test the claim for the odd index \(n=3\) using \(a=-2\). c) Correct the general formula for every even positive integer \(n\) so that it is valid for all real \(a\).

Hints

- Compute the power first in each example. - Compare the behavior of negative bases under even and odd powers. - The principal value of an even-index root is never negative.

Solution

1. \(\sqrt[4]{(-3)^4}=\sqrt[4]{81}=3\), not \(-3\), so the claim is false for this even index and negative input. 2. \(\sqrt[3]{(-2)^3}=\sqrt[3]{-8}=-2\), so the claim is true in this odd-index example. 3. A principal even root is nonnegative. Therefore, for even \(n\), the correct formula is \(\sqrt[n]{a^n}=|a|\).

Answer

a) False: \(\sqrt[4]{(-3)^4}=3\). b) True: \(\sqrt[3]{(-2)^3}=-2\). c) For even \(n\), \(\sqrt[n]{a^n}=|a|\).
5248209
Use radical and exponent properties to solve each part. a) Write \(\sqrt{b\sqrt[3]{b}}\) as a single radical, where \(b>0\). b) Simplify \(\sqrt[4]{49p^2}\), where \(p>0\). c) Use rational exponents to show that \(\sqrt[3]{2}\cdot\sqrt[6]{2}=\sqrt2\).

Hints

- Rewrite radicals as rational exponents. - Work from the inner radical outward in part a). - Reduce the exponent fraction in part b). - Add exponents when multiplying powers with the same base.

Solution

1. \(\sqrt{b\sqrt[3]{b}}=\left(b\cdot b^{\frac13}\right)^{\frac12}=b^{\frac23}=\sqrt[3]{b^2}\). 2. \(\sqrt[4]{49p^2}=\sqrt[4]{(7p)^2}=(7p)^{\frac24}=\sqrt{7p}\). 3. \(\sqrt[3]{2}\cdot\sqrt[6]{2}=2^{\frac13}2^{\frac16}=2^{\frac13+\frac16}=2^{\frac12}=\sqrt2\).

Answer

a) \(\sqrt[3]{b^2}\) b) \(\sqrt{7p}\) c) The exponents add to \(\frac12\), so the equation is true.
5248649
For \(x>0\) and \(y>0\), let \(E=\frac{x^{\frac23}-y^{\frac23}}{x^{\frac13}+y^{\frac13}}\). a) Simplify \(E\) completely. b) Evaluate \(E\) when \(x=27\) and \(y=8\).

Hints

- Recognize the numerator as a difference of squares. - Use \(x^{\frac23}=\left(x^{\frac13}\right)^2\). - Factor before canceling. - Interpret an exponent of \(\frac13\) as a cube root.

Solution

1. Write the numerator as a difference of squares: \(x^{\frac23}-y^{\frac23}=\left(x^{\frac13}\right)^2-\left(y^{\frac13}\right)^2\). 2. Factor: \(x^{\frac23}-y^{\frac23}=\left(x^{\frac13}-y^{\frac13}\right)\left(x^{\frac13}+y^{\frac13}\right)\). 3. Since the denominator is positive, cancel the common factor to obtain \(E=x^{\frac13}-y^{\frac13}\). 4. For \(x=27\) and \(y=8\), \(E=27^{\frac13}-8^{\frac13}=3-2=1\).

Answer

a) \(E=x^{\frac13}-y^{\frac13}\) b) \(1\)
5249029
Simplify each expression completely. Assume \(y>0\), \(k>0\), and \(z>0\). 1) \(\frac{\sqrt[3]{y^2}\sqrt[6]{y^5}}{\sqrt y}\) 2) \(\frac{\sqrt[3]{k^2}\sqrt[4]{k^3}}{\sqrt[12]{k}}\) 3) \(\frac{\sqrt[5]{z^4}}{\sqrt[15]{z^2}}\)

Hints

- Rewrite every radical as a rational exponent. - Add numerator exponents and subtract denominator exponents. - Reduce the final exponent fraction. - For an improper fractional exponent, separate the whole-number part.

Solution

1. \(y^{\frac23+\frac56-\frac12}=y^{\frac46+\frac56-\frac36}=y\). 2. \(k^{\frac23+\frac34-\frac1{12}}=k^{\frac8{12}+\frac9{12}-\frac1{12}}=k^{\frac43}=k\sqrt[3]{k}\). 3. \(z^{\frac45-\frac2{15}}=z^{\frac{12}{15}-\frac2{15}}=z^{\frac23}=\sqrt[3]{z^2}\).

Answer

1) \(y\) 2) \(k\sqrt[3]{k}\) 3) \(\sqrt[3]{z^2}\)
5249089
Decide whether each statement is true or false. Justify your answer using exponent properties. In part a), assume \(x\ge0\), and in part b), assume \(a\ge0\). a) \(\sqrt[3]{x^2}\cdot\sqrt[3]{x}=x\) b) \(\sqrt{\sqrt[3]{a}}=a^{\frac15}\) c) \(16^{-\frac14}=0.5\)

Hints

- Rewrite each radical as a rational exponent. - Add exponents when multiplying like bases. - Multiply exponents for nested powers. - Interpret a negative exponent as a reciprocal.

Solution

1. \(\sqrt[3]{x^2}\cdot\sqrt[3]{x}=x^{\frac23}x^{\frac13}=x\), so a) is true. 2. \(\sqrt{\sqrt[3]{a}}=\left(a^{\frac13}\right)^{\frac12}=a^{\frac16}\), not \(a^{\frac15}\) in general. For example, when \(a=64\), the left side is \(2\), while \(64^{\frac15}\ne2\). Thus b) is false. 3. \(16^{-\frac14}=\frac1{16^{\frac14}}=\frac12=0.5\), so c) is true.

Answer

a) True b) False c) True
5249109
For \(x>0\), let \(T=\frac1{\sqrt[4]{x^3}}\). a) Write \(T\) as a power with a rational exponent. b) Evaluate \(T\) when \(x=16\). c) Use exponent properties to show that \(T\cdot x=\sqrt[4]{x}\).

Hints

- A radical in the denominator can be written using a negative exponent. - Evaluate the fourth root of \(16\) before applying the cube. - Write \(x\) as \(x^1\) and add exponents.

Solution

1. Since \(\sqrt[4]{x^3}=x^{\frac34}\), \(T=x^{-\frac34}\). 2. When \(x=16\), \(T=16^{-\frac34}=\frac1{(\sqrt[4]{16})^3}=\frac1{2^3}=\frac18\). 3. \(T\cdot x=x^{-\frac34}x^1=x^{\frac14}=\sqrt[4]{x}\).

Answer

a) \(T=x^{-\frac34}\) b) \(\frac18\) c) \(T\cdot x=x^{\frac14}=\sqrt[4]{x}\)
5249149
Simplify each expression completely and write the result without a radical. Assume all variables are positive. 1. \((3\sqrt[3]{2})^3\) 2. \(\frac{(\sqrt[6]{5})^{12}}5\) 3. \((\sqrt[4]{4})^2\) 4. \(\frac{(\sqrt[3]{y})^9}{y^2}\)

Hints

- Apply an outside exponent to every factor in a product. - Rewrite radicals as rational exponents. - Multiply exponents for a power raised to another power. - Subtract exponents when dividing like bases.

Solution

1. \((3\sqrt[3]{2})^3=3^3(\sqrt[3]{2})^3=27\cdot2=54\). 2. \(\frac{(\sqrt[6]{5})^{12}}5=\frac{5^{\frac{12}{6}}}{5}=5\). 3. \((\sqrt[4]{4})^2=(4^{\frac14})^2=4^{\frac12}=2\). 4. \(\frac{(\sqrt[3]{y})^9}{y^2}=y^{\frac93-2}=y^{3-2}=y\).

Answer

1. \(54\) 2. \(5\) 3. \(2\) 4. \(y\)
5249199
For \(x>0\) and \(y>0\), simplify the expression using exponent properties. Write the final result with one radical and no fractional exponents: \(\frac{(x^2y^3)^{\frac14}}{\sqrt[4]{xy^{-1}}}\)

Hints

- Rewrite the fourth root as an exponent of \(\frac14\). - Distribute the exponent over each product. - Subtract denominator exponents from numerator exponents. - Convert the remaining fractional exponent back to a radical.

Solution

1. Rewrite the denominator as a rational exponent and distribute the exponents: \(\frac{x^{\frac24}y^{\frac34}}{x^{\frac14}y^{-\frac14}}\). 2. Subtract exponents for each base: \(x^{\frac24-\frac14}y^{\frac34-(-\frac14)}=x^{\frac14}y\). 3. Convert the remaining fractional exponent to a radical: \(y\sqrt[4]{x}\).

Answer

\(y\sqrt[4]{x}\)
5249209
For \(a>0\) and \(b>0\), let \(T=\frac{\sqrt{a^3\sqrt[3]{b^2}}}{\sqrt[3]{ab}}\). a) Simplify \(T\) using rational exponents. b) Evaluate \(T\) when \(a=64\) and \(b=27\).

Hints

- Rewrite nested radicals from the inside outward. - Distribute each rational exponent over its product. - Subtract exponents when dividing like bases. - Express \(64\) as a power of \(2\).

Solution

1. Rewrite the radicals: \(T=\frac{(a^3b^{\frac23})^{\frac12}}{(ab)^{\frac13}}\). 2. Distribute the exponents: \(T=\frac{a^{\frac32}b^{\frac13}}{a^{\frac13}b^{\frac13}}\). 3. Cancel the powers of \(b\) and subtract the exponents of \(a\): \(T=a^{\frac32-\frac13}=a^{\frac76}\). 4. For \(a=64=2^6\), \(T=64^{\frac76}=(2^6)^{\frac76}=2^7=128\).

Answer

a) \(a^{\frac76}\) b) \(128\)
5249229
Compare each pair without a calculator. Insert \(<\), \(>\), or \(=\), and briefly justify your answer. a) \(\sqrt[3]{5}\) and \(\sqrt3\) b) \(\sqrt[4]{10}\) and \(\sqrt[3]{4}\) c) \(\sqrt[6]{10}\) and \(\sqrt[3]{3}\)

Hints

- Rewrite each pair with a common radical index. - Use the least common multiple of the two indices. - Once the indices match, compare the radicands.

Solution

1. For part a, use a common index of \(6\): \(\sqrt[3]{5}=\sqrt[6]{25}\) and \(\sqrt3=\sqrt[6]{27}\). Since \(25<27\), \(\sqrt[3]{5}<\sqrt3\). 2. For part b, use a common index of \(12\): \(\sqrt[4]{10}=\sqrt[12]{1000}\) and \(\sqrt[3]{4}=\sqrt[12]{256}\). Since \(1000>256\), \(\sqrt[4]{10}>\sqrt[3]{4}\). 3. For part c, use a common index of \(6\): \(\sqrt[3]{3}=\sqrt[6]{9}\). Since \(10>9\), \(\sqrt[6]{10}>\sqrt[3]{3}\).

Answer

a) \(\sqrt[3]{5}<\sqrt3\) b) \(\sqrt[4]{10}>\sqrt[3]{4}\) c) \(\sqrt[6]{10}>\sqrt[3]{3}\)
5249269
Let \(T=(-2x\sqrt[5]{x^2})^3\). 1) Simplify \(T\) completely. 2) Determine whether \(T\) is negative for every \(x>0\). Briefly justify your conclusion.

Hints

- Apply the cube to every factor in the product. - Rewrite the fifth root as a rational exponent. - Separate an improper fractional exponent into a whole-number and fractional part. - Analyze the sign of each factor for \(x>0\).

Solution

1. Apply the exponent to each factor: \(T=(-2)^3x^3(\sqrt[5]{x^2})^3=-8x^3x^{\frac65}\). 2. Combine the powers of \(x\): \(T=-8x^{3+\frac65}=-8x^{\frac{21}{5}}=-8x^4\sqrt[5]{x}\). 3. For \(x>0\), both \(x^4\) and \(\sqrt[5]{x}\) are positive. Multiplying them by \(-8\) makes \(T\) negative.

Answer

1) \(-8x^4\sqrt[5]{x}\) 2) Yes. The variable factors are positive for \(x>0\), and the coefficient is negative.
5249319
For \(a>0\) and \(b>0\), simplify completely: \(\left(\frac{a^2}{b}\sqrt[3]{\frac{b^2}{a^3}}\right)^3\)

Hints

- Apply the outside cube to both factors inside the parentheses. - A cube and a cube root undo each other. - Subtract exponents when dividing powers with the same base.

Solution

1. Apply the cube to each factor: \(\left(\frac{a^2}{b}\right)^3\left(\sqrt[3]{\frac{b^2}{a^3}}\right)^3\). 2. This gives \(\frac{a^6}{b^3}\cdot\frac{b^2}{a^3}\). 3. Subtract exponents on like bases: \(a^{6-3}b^{2-3}=a^3b^{-1}=\frac{a^3}{b}\).

Answer

\(\frac{a^3}{b}\)
5249329
For \(x>0\), write the expression as a single power or simple radical without negative exponents: \(\frac{\sqrt{x\sqrt[3]{x^2}}}{x\sqrt[6]{x}}\)

Hints

- Rewrite all radicals as rational exponents. - Simplify the numerator and denominator separately. - Subtract exponents when dividing like bases. - Convert a negative exponent to a reciprocal.

Solution

1. Simplify the numerator: \(\sqrt{x\sqrt[3]{x^2}}=\left(x\cdot x^{\frac23}\right)^{\frac12}=x^{\frac56}\). 2. Simplify the denominator: \(x\sqrt[6]{x}=x^{1+\frac16}=x^{\frac76}\). 3. Divide the powers: \(x^{\frac56-\frac76}=x^{-\frac13}=\frac1{\sqrt[3]{x}}\).

Answer

\(\frac1{\sqrt[3]{x}}\)
5249399
For \(a>0\), use exponent properties to simplify completely: \(\left(\frac{a^2\sqrt a}{\sqrt[3]{a^2}}\right)^6\)

Hints

- Rewrite each radical as a rational exponent. - Simplify the expression inside the parentheses first. - Add or subtract exponents on like bases. - Multiply exponents when raising a power to another power.

Solution

1. Rewrite the radicals: \(\sqrt a=a^{\frac12}\) and \(\sqrt[3]{a^2}=a^{\frac23}\). 2. Simplify inside the parentheses: \(\frac{a^{2+\frac12}}{a^{\frac23}}=a^{\frac52-\frac23}=a^{\frac{11}{6}}\). 3. Raise the power to the sixth power: \(\left(a^{\frac{11}{6}}\right)^6=a^{11}\).

Answer

\(a^{11}\)
5249409
For \(x\ne0\) and \(x\ne y\), simplify completely: \(\left(\frac{x-y}{x}\sqrt[3]{\frac{x^2}{x-y}}\right)^6\)

Hints

- Apply the outside exponent to each factor. - A cube root raised to the sixth power produces a square. - Multiply the resulting rational expressions. - Cancel like factors by subtracting exponents.

Solution

1. Apply the sixth power to both factors: \(\left(\frac{x-y}{x}\right)^6\left(\sqrt[3]{\frac{x^2}{x-y}}\right)^6\). 2. Simplify each factor: \(\frac{(x-y)^6}{x^6}\left(\frac{x^2}{x-y}\right)^2\). 3. Multiply and subtract exponents on like factors: \(\frac{(x-y)^6x^4}{x^6(x-y)^2}=\frac{(x-y)^4}{x^2}\).

Answer

\(\frac{(x-y)^4}{x^2}\)
5249509
For \(x>0\) and \(y>0\), simplify completely. The final expression should have no parentheses, and each base should appear only once. \(\frac{(x^{\frac14}y^{-\frac12})^4}{xy^{-3}}\)

Hints

- Distribute the outside exponent over the product. - Multiply exponents in the numerator. - Subtract denominator exponents from numerator exponents. - Recall that a nonzero number raised to the zero power equals \(1\).

Solution

1. Apply the fourth power to each factor in the numerator: \((x^{\frac14}y^{-\frac12})^4=xy^{-2}\). 2. Divide powers with the same bases: \(\frac{xy^{-2}}{xy^{-3}}=x^{1-1}y^{-2-(-3)}\). 3. This simplifies to \(x^0y=y\).

Answer

\(y\)
5249739
A student claims that \(\sqrt{p^5\sqrt p}\), for \(p>0\), is equivalent to \(\sqrt[4]{p^{11}}\). Verify the claim in two ways: 1. Rewrite all radicals as rational exponents and apply exponent properties. 2. Move the factor \(p^5\) under the inner square root and combine the nested radicals.

Hints

- Rewrite each square root as an exponent of \(\frac12\). - Add exponents on like bases before applying the outside square root. - To move a positive factor under a square root, square it. - Two nested square roots combine to a fourth root.

Solution

1. Using rational exponents, \(\sqrt{p^5\sqrt p}=\left(p^5p^{\frac12}\right)^{\frac12}=p^{\left(5+\frac12\right)\frac12}=p^{\frac{11}{4}}=\sqrt[4]{p^{11}}\). 2. Since \(p>0\), \(p^5=\sqrt{p^{10}}\). Thus \(\sqrt{p^5\sqrt p}=\sqrt{\sqrt{p^{10}}\sqrt p}=\sqrt{\sqrt{p^{11}}}=\sqrt[4]{p^{11}}\). 3. Both methods confirm the claim.

Answer

The claim is true. Both methods give \(\sqrt[4]{p^{11}}\).
5249749
For positive \(a\) and \(b\), simplify \(Q=\sqrt[3]{\frac{a^2}{b}\sqrt{\frac ba}}\). Write the final result as a single radical and briefly identify the exponent properties used.

Hints

- Rewrite both radicals as rational exponents. - Distribute exponents over products and quotients. - Combine powers with the same base. - Give the final exponents a common denominator to form one radical.

Solution

1. Rewrite the expression with rational exponents: \(Q=\left(a^2b^{-1}(ba^{-1})^{\frac12}\right)^{\frac13}\). 2. Distribute the square-root exponent and combine like bases inside the cube root: \(Q=\left(a^{2-\frac12}b^{-1+\frac12}\right)^{\frac13}=\left(a^{\frac32}b^{-\frac12}\right)^{\frac13}\). 3. Multiply exponents: \(Q=a^{\frac12}b^{-\frac16}=a^{\frac36}b^{-\frac16}=\left(\frac{a^3}{b}\right)^{\frac16}\). 4. Therefore \(Q=\sqrt[6]{\frac{a^3}{b}}\). The work uses the power-of-a-product, product-of-powers, and power-of-a-power properties.

Answer

\(Q=\sqrt[6]{\frac{a^3}{b}}\)
5249789
Use powers with base \(2\) to analyze each relationship. a) Show that \(\sqrt{2\sqrt[3]{4}}=\sqrt[3]{4\sqrt2}\). b) Find \(k\) if \(\sqrt[3]{\frac12\sqrt{\frac12}}=2^k\).

Hints

- Rewrite every quantity as a power of \(2\). - Add exponents on factors with the same base. - A reciprocal has a negative exponent. - Compare the final exponents.

Solution

1. The left side is \(\left(2^1\cdot2^{\frac23}\right)^{\frac12}=2^{\frac56}\). 2. The right side is \(\left(2^2\cdot2^{\frac12}\right)^{\frac13}=2^{\frac56}\). Therefore the equation in part a) is true. 3. For part b), \(\frac12=2^{-1}\), so \(\sqrt[3]{\frac12\sqrt{\frac12}}=\left(2^{-1}2^{-\frac12}\right)^{\frac13}=2^{-\frac12}\). 4. Comparing exponents gives \(k=-\frac12\).

Answer

a) Both sides equal \(2^{\frac56}\). b) \(k=-\frac12\)
5249809
For \(a>0\), determine whether the equation \(\sqrt{a\sqrt[4]{a^3}}=\sqrt[8]{a^7}\) is true for every allowed value of \(a\). Then simplify the following expression for \(z>0\): \(\sqrt[4]{\frac z{\sqrt z}}\)

Hints

- Rewrite both sides using rational exponents. - Simplify the product inside the square root before applying the outer exponent. - Subtract exponents when dividing like bases. - Multiply exponents for nested powers.

Solution

1. The left side is \(\left(a\cdot a^{\frac34}\right)^{\frac12}=a^{\frac78}\). 2. The right side is \(\sqrt[8]{a^7}=a^{\frac78}\), so the equation is true for every \(a>0\). 3. For the second expression, \(\sqrt[4]{\frac z{\sqrt z}}=\left(z^{1-\frac12}\right)^{\frac14}=z^{\frac18}=\sqrt[8]{z}\).

Answer

The equation is true because both sides equal \(a^{\frac78}\). The second expression simplifies to \(\sqrt[8]{z}\).
5249929
Use exponent properties to solve each part. a) Evaluate \((\sqrt3\cdot\sqrt[6]{3})^{-3}\). b) Compare \(A=(\sqrt[4]{16})^3\) and \(B=(\sqrt[3]{16})^{\frac32}\). Which expression has the greater value? Justify your answer algebraically.

Hints

- Rewrite all radicals as rational exponents. - Add exponents on like bases before applying the outside exponent. - Multiply exponents in a power raised to another power. - Simplify each expression exactly before comparing.

Solution

1. \((\sqrt3\cdot\sqrt[6]{3})^{-3}=\left(3^{\frac12}3^{\frac16}\right)^{-3}=\left(3^{\frac23}\right)^{-3}=3^{-2}=\frac19\). 2. \(A=(\sqrt[4]{16})^3=2^3=8\). 3. \(B=(16^{\frac13})^{\frac32}=16^{\frac12}=4\). 4. Since \(8>4\), \(A>B\).

Answer

a) \(\frac19\) b) \(A\) is greater because \(A=8\) and \(B=4\).
5250009
For \(y>0\), let \(T=\frac{\sqrt[3]{y}\,y^2}{\sqrt{y^3}}\). a) Simplify \(T\) and write the result in the form \(y^k\). b) Evaluate \(T\) when \(y=64\).

Hints

- Rewrite every radical as a rational exponent. - Add numerator exponents and subtract the denominator exponent. - Use a common denominator for the exponent fractions. - For the numerical value, take the sixth root before raising to the fifth power.

Solution

1. Rewrite the radicals: \(T=y^{\frac13+2-\frac32}\). 2. Combine the exponents: \(\frac13+2-\frac32=\frac2{6}+\frac{12}{6}-\frac9{6}=\frac56\). Thus \(T=y^{\frac56}\), so \(k=\frac56\). 3. For \(y=64\), \(T=64^{\frac56}=(\sqrt[6]{64})^5=2^5=32\).

Answer

a) \(T=y^{\frac56}\), so \(k=\frac56\). b) \(32\)
5250699
For \(x>0\), rational \(n\), and \(x^n\ne1\), let \(T=\left(\frac{x^n}{x^n-1}-\frac{x^n}{x^n+1}\right)\frac{x^{2n}-1}{2}\). 1. Simplify \(T\) completely. 2. Evaluate \(T\) when \(x=16\) and \(n=0.75\).

Hints

- Combine the two fractions using a common denominator. - Use the difference-of-squares identity in the denominator. - Simplify algebraically before substituting values. - Rewrite the decimal exponent as a fraction.

Solution

1. Use the common denominator \((x^n-1)(x^n+1)=x^{2n}-1\). 2. The numerator of the difference is \(x^n(x^n+1)-x^n(x^n-1)=2x^n\), so the expression in parentheses is \(\frac{2x^n}{x^{2n}-1}\). 3. Multiply and cancel: \(T=\frac{2x^n}{x^{2n}-1}\cdot\frac{x^{2n}-1}{2}=x^n\). 4. Since \(0.75=\frac34\), \(T=16^{\frac34}=(\sqrt[4]{16})^3=8\).

Answer

1. \(T=x^n\) 2. \(8\)
5250879
Evaluate the numerical expression: \(A=(0.125)^{-\frac13}\cdot(0.25)^{0.5}+(3^2)^{1.5}-\sqrt[4]{81^3}+(5.7)^0\)

Hints

- Rewrite terminating decimals as fractions when helpful. - Multiply exponents in a power raised to another power. - A negative exponent represents a reciprocal. - Any nonzero number raised to the zero power equals \(1\).

Solution

1. Since \(0.125=\frac18=2^{-3}\), \((0.125)^{-\frac13}=(2^{-3})^{-\frac13}=2\). 2. \((0.25)^{0.5}=\sqrt{\frac14}=\frac12\), so the product of the first two factors is \(1\). 3. \((3^2)^{1.5}=3^{2\cdot\frac32}=3^3=27\). 4. \(\sqrt[4]{81^3}=(81^{\frac14})^3=3^3=27\). 5. Since \(5.7\ne0\), \((5.7)^0=1\). 6. Therefore \(A=1+27-27+1=2\).

Answer

\(2\)
5253509
Solve each equation over the real numbers. a) \(\left(11+\sqrt[3]{x-5}\right)^{\frac{1}{2}}=3\) b) \((x-4)^{\frac{2}{3}}=4\). Briefly explain why this equation has two solutions.

Hints

- Work from the outermost operation inward. - A cube root can be negative. - Rewrite the exponent \(\frac{2}{3}\) as a cube root followed by a square.

Solution

1. Square both sides of part a: \(11+\sqrt[3]{x-5}=9\). Then \(\sqrt[3]{x-5}=-2\). 2. Cube both sides: \(x-5=-8\), so \(x=-3\). Substitution gives \(\sqrt{9}=3\), so the solution is valid. 3. For part b, write \((x-4)^{\frac{2}{3}}=\left(\sqrt[3]{x-4}\right)^2\). Thus \(\sqrt[3]{x-4}=\pm2\). 4. Cube each case: \(x-4=8\) or \(x-4=-8\). Therefore, \(x=12\) or \(x=-4\). There are two solutions because both \(2\) and \(-2\) have square \(4\).

Answer

a) \(x=-3\) b) \(\{-4,12\}\). The square in the exponent allows both a positive and a negative cube-root value.
5283779
Find the positive base \(b\) of the exponential function \(y=b^x\) that passes through each point. a) \(P(4, 81)\) b) \(Q(-3, 0.125)\) c) \(R(1.5, 8)\)

Hints

- Substitute each point's coordinates into the function equation. - Use roots or reciprocal exponents to isolate the base. - Apply properties of negative and rational exponents. - Convert convenient decimals to fractions.

Solution

1. Substitute each point into \(y=b^x\) and solve for \(b\). 2. For \(P(4, 81)\), \(81=b^4\), so \(b=81^{1/4}=3\). 3. For \(Q(-3, 0.125)\), \(0.125=b^{-3}\). Since \(0.125=\frac{1}{8}\), \(b^3=8\), so \(b=2\). 4. For \(R(1.5, 8)\), \(8=b^{3/2}\), so \(b=8^{2/3}=4\).

Answer

a) \(b=3\) b) \(b=2\) c) \(b=4\)
5326599
Match each function to graph \(a\), \(b\), \(c\), or \(d\) in the image. Justify each match. 1) \(f(x)=x^{-1}\) 2) \(g(x)=x^{\frac{1}{2}}\) 3) \(h(x)=x^{\frac{3}{2}}\) 4) \(k(x)=\frac{1}{4}x^2\)
Figure for problem 532659

Hints

- Compare the graphs near \(x=0\) and for larger positive values of \(x\). - Evaluate each function at simple inputs such as \(1\), \(2\), and \(4\). - Decide whether each graph becomes steeper or less steep as \(x\) increases. - Which function is decreasing for \(x>0\)?

Solution

1. Graph \(c\) is the only graph that decreases for \(x>0\) and approaches positive infinity as \(x\to0^+\). Therefore, \(f(x)=x^{-1}\) matches graph \(c\). 2. The function \(g(x)=\sqrt{x}\) passes through \((1, 1)\) and \((4, 2)\) and increases while becoming less steep. It matches graph \(a\). 3. The function \(h(x)=x^{3/2}\) passes through \((0, 0)\) and \((1, 1)\) and increases while becoming steeper. It matches graph \(b\). 4. The function \(k(x)=\frac{1}{4}x^2\) passes through \((0, 0)\), \((2, 1)\), and \((4, 4)\). It matches graph \(d\).

Answer

1) Graph \(c\) 2) Graph \(a\) 3) Graph \(b\) 4) Graph \(d\)
5326609
The image shows three graphs labeled \(u\), \(v\), and \(w\) and the marked points \(P(4, 3)\), \(Q(4, 4)\), and \(R(2, 1)\). (A) \(f(x)=1.5x^{0.5}\) (B) \(g(x)=0.5x^{1.5}\) (C) \(h(x)=2x^{-1}\) a) Match each function to graph \(u\), \(v\), or \(w\). b) Justify the matches in two ways: first by testing the marked points, and then by describing each graph's behavior for \(x>0\).
Figure for problem 532660

Hints

- Test the x-coordinates of the marked points in the three functions. - A point lies on a graph when its coordinates satisfy the function rule. - Identify which graph decreases for positive \(x\). - Compare how graphs with exponents below and above \(1\) change in steepness.

Solution

1. For function A, \(f(4)=1.5\cdot4^{0.5}=1.5\cdot2=3\), so \(P(4, 3)\) lies on its graph. Function A matches graph \(u\). 2. For function B, \(g(4)=0.5\cdot4^{1.5}=0.5\cdot8=4\), so \(Q(4, 4)\) lies on its graph. Function B matches graph \(v\). 3. For function C, \(h(2)=2\cdot2^{-1}=1\), so \(R(2, 1)\) lies on its graph. Function C matches graph \(w\). 4. Graph \(w\) decreases, approaches positive infinity as \(x\to0^+\), and approaches \(0\) as \(x\to\infty\), which matches a negative exponent. 5. Graph \(u\) increases while becoming less steep, which matches an exponent between \(0\) and \(1\). Graph \(v\) increases while becoming steeper, which matches an exponent greater than \(1\).

Answer

a) Function A matches graph \(u\), function B matches graph \(v\), and function C matches graph \(w\). b) The marked-point checks are \(f(4)=3\), \(g(4)=4\), and \(h(2)=1\). Graph \(w\) has reciprocal behavior, graph \(u\) increases while flattening, and graph \(v\) increases while becoming steeper.
5334979
Match graphs \(f_1\), \(f_2\), and \(f_3\) to the correct function rules. - \(a(x)=\frac{1}{x^2}\) - \(b(x)=-\frac{1}{x}\) - \(c(x)=\sqrt{x}\) Justify each match using domain, sign, or symmetry.
Figure for problem 533497

Hints

- Compare the domains of the three functions. - Determine which graphs have only positive outputs. - Use y-axis or origin symmetry to distinguish the reciprocal functions.

Solution

1. Graph \(f_3\) is defined only for nonnegative inputs and begins at the origin, so it represents \(c(x)=\sqrt{x}\). 2. Graph \(f_1\) has only positive outputs and is symmetric about the y-axis, so it represents \(a(x)=\frac{1}{x^2}\). 3. Graph \(f_2\) lies in Quadrants II and IV. This matches \(b(x)=-\frac{1}{x}\), which is the graph of \(\frac{1}{x}\) reflected across the x-axis.

Answer

\(f_1: a(x)=\frac{1}{x^2}\); \(f_2: b(x)=-\frac{1}{x}\); \(f_3: c(x)=\sqrt{x}\)
5345649
The image shows three power functions of the form \(y=x^n\), where \(n\) is an integer. a) Based on each graph's shape, decide whether its exponent is even or odd. b) Match the graphs to \(k(x)=x^4\), \(m(x)=x^3\), and \(p(x)=x^{-2}\).
Figure for problem 534564

Hints

- Use y-axis symmetry and origin symmetry. - Determine which graphs pass through the origin. - A negative exponent creates a vertical asymptote at \(x=0\).

Solution

1. Graph \(s\) is symmetric about the origin, so its exponent is odd. It represents \(m(x)=x^3\). 2. Graph \(r\) is symmetric about the y-axis and passes through the origin, so it has a positive even exponent. It represents \(k(x)=x^4\). 3. Graph \(t\) is symmetric about the y-axis but is undefined at \(x=0\) and approaches the y-axis. It has a negative even exponent and represents \(p(x)=x^{-2}\).

Answer

a) Graph \(r\): even; graph \(s\): odd; graph \(t\): even b) \(r: k(x)=x^4\); \(s: m(x)=x^3\); \(t: p(x)=x^{-2}\)
5345659
Match graphs \(p\), \(q\), \(r\), and \(s\) to four of the function rules below. Justify your choices using key values such as \(x=1\) or \(x=2\), or by comparing how the functions grow. - \(f(x)=3x^{0.5}\) - \(g(x)=x^2\) - \(h(x)=\frac{4}{x}\) - \(k(x)=0.5x^3\) - \(m(x)=x^{-2}\)
Figure for problem 534565

Hints

- Evaluate each rule at \(x=1\). - Identify which graph decreases as \(x\) increases. - Use a second input to distinguish graphs that intersect. - Compare the shapes of square-root, quadratic, cubic, and reciprocal functions.

Solution

1. Graph \(p\) passes through \((1, 3)\), matching \(f(1)=3\). Thus, graph \(p\) represents \(f\). 2. Graph \(r\) decreases for positive \(x\) and passes through \((1, 4)\), matching \(h(x)=\frac{4}{x}\). 3. Graphs \(q\) and \(s\) meet at \((2, 4)\). At \(x=1\), graph \(q\) has value \(1\), matching \(g(1)=1\), while graph \(s\) has value \(0.5\), matching \(k(1)=0.5\). 4. The remaining rule, \(m(x)=x^{-2}\), would have values \(m(1)=1\) and \(m(2)=0.25\), which do not match any displayed graph.

Answer

Graph \(p\): \(f(x)=3x^{0.5}\) Graph \(q\): \(g(x)=x^2\) Graph \(r\): \(h(x)=\frac{4}{x}\) Graph \(s\): \(k(x)=0.5x^3\)
5345669
Match graphs \(u\), \(v\), \(w\), and \(z\) to four of the function rules below. Briefly justify each match mathematically. - \(p(x)=\sqrt[3]{x}\) - \(q(x)=x^{-0.5}\) - \(r(x)=1.5\sqrt{x}\) - \(s(x)=-0.2x^2\) - \(t(x)=2x^{-1}\)
Figure for problem 534566

Hints

- A negative leading coefficient makes the quadratic outputs negative for positive inputs. - Functions with negative exponents decrease for positive inputs. - Evaluate the rules at \(x=1\) and \(x=4\). - Recall that \(x^{0.5}=\sqrt{x}\).

Solution

1. Graph \(z\) passes through the origin and has negative outputs for positive inputs, so it matches \(s(x)=-0.2x^2\). 2. Graph \(v\) decreases and passes through \((1, 1)\) and \((4, 0.5)\). Since \(4^{-0.5}=\frac{1}{\sqrt{4}}=0.5\), it matches \(q\). 3. Graph \(w\) passes through \((1, 1.5)\) and \((4, 3)\), matching \(r(x)=1.5\sqrt{x}\). 4. Graph \(u\) passes through \((1, 1)\) and has a value near \(1.6\) at \(x=4\). Since \(\sqrt[3]{4}\approx1.587\), it matches \(p\). 5. The rule \(t(x)=2x^{-1}\) would pass through \((1, 2)\), so it is the unused rule.

Answer

Graph \(u\): \(p(x)=\sqrt[3]{x}\) Graph \(v\): \(q(x)=x^{-0.5}\) Graph \(w\): \(r(x)=1.5\sqrt{x}\) Graph \(z\): \(s(x)=-0.2x^2\)
5345679
Find the rule for the power function \(f(x)=ax^n\) shown in the graph. The graph passes exactly through the marked grid points.
Figure for problem 534567

Hints

- The point with \(x=1\) makes it easy to find \(a\). - Use the second point to form an equation for \(n\). - Rewrite \(\frac{1}{2}\) as a power of \(2\).

Solution

1. Read the marked points: \(P(1, 2)\) and \(Q(2, 1)\). 2. Substitute \(P\): \(2=a(1^n)\), so \(a=2\). 3. Substitute \(Q\): \(1=2\cdot2^n\), so \(2^n=\frac{1}{2}=2^{-1}\). 4. Therefore, \(n=-1\), and \(f(x)=2x^{-1}=\frac{2}{x}\).

Answer

\(f(x)=2x^{-1}\), or equivalently \(f(x)=\frac{2}{x}\)
5345689
A power function \(g(x)=ax^n\) passes through \(P(1, 0.5)\) and \(Q(4, 4)\). Find \(a\) and \(n\) algebraically, write the complete function rule, and check it against the graph.
Figure for problem 534568

Hints

- Substitute the point with \(x=1\) first to find \(a\). - Use the second point to form an equation for \(n\). - Rewrite both sides as powers with the same base.

Solution

1. Substitute \(P(1, 0.5)\): \(0.5=a(1^n)\), so \(a=0.5\). 2. Substitute \(Q(4, 4)\): \(4=0.5\cdot4^n\). 3. Multiply by \(2\): \(8=4^n\). 4. Write both sides with base \(2\): \(2^3=(2^2)^n=2^{2n}\). 5. Thus, \(3=2n\), so \(n=\frac{3}{2}\). Therefore, \(g(x)=0.5x^{3/2}\). 6. The rule gives \(g(1)=0.5\) and \(g(4)=4\) and has the same increasing, upward-curving shape shown for \(x\ge0\), so it matches the graph.

Answer

\(a=0.5\), \(n=\frac{3}{2}\), and \(g(x)=0.5x^{3/2}\)
5149019
Compare \(u=\sqrt[3]{5}\) and \(v=\sqrt[4]{8}\) without a calculator. Which is greater? Justify your answer algebraically.

Hints

- Rewrite both radicals with the same index. - Use the least common multiple of \(3\) and \(4\). - Once the indices match, compare the radicands.

Solution

1. Use a common radical index. The least common multiple of \(3\) and \(4\) is \(12\). 2. \(u=\sqrt[12]{5^4}=\sqrt[12]{625}\), and \(v=\sqrt[12]{8^3}=\sqrt[12]{512}\). 3. Since \(625>512\), \(\sqrt[12]{625}>\sqrt[12]{512}\). Therefore, \(u>v\).

Answer

\(\sqrt[3]{5}>\sqrt[4]{8}\)
5250609
For \(x>0\), \(y>0\), and positive integer \(k\), simplify \(\left(\frac{x^k+y^k}{x^{-k}+y^{-k}}\right)^{-\frac1k}\). Then evaluate the expression for \(x=0.25\), \(y=8\), and \(k=3\).

Hints

- Rewrite negative exponents as reciprocals. - Combine the two fractions in the denominator. - Simplify the complex fraction before applying the outside exponent. - Multiply exponents in a power raised to another power.

Solution

1. Rewrite the denominator: \(x^{-k}+y^{-k}=\frac1{x^k}+\frac1{y^k}=\frac{x^k+y^k}{x^ky^k}\). 2. The fraction inside the parentheses becomes \(\frac{x^k+y^k}{\frac{x^k+y^k}{x^ky^k}}=x^ky^k=(xy)^k\). 3. Apply the outside exponent: \(((xy)^k)^{-\frac1k}=(xy)^{-1}=\frac1{xy}\). 4. For \(x=0.25\) and \(y=8\), the value is \(\frac1{0.25\cdot8}=\frac12\).

Answer

The simplified expression is \(\frac1{xy}\). Its value is \(\frac12\).
5250709
For \(a>0\), \(b>0\), nonzero rational \(n\), and \(a\ne b\), simplify \(A=\left(\frac{a^{-n}}{a^{-n}-b^{-n}}-\frac{a^{-n}}{a^{-n}+b^{-n}}\right)(a^{-n}+b^{-n})\). Then evaluate \(A\) when \(a=4\), \(b=25\), and \(n=0.5\).

Hints

- Find a common denominator for the two fractions in parentheses. - Use the difference-of-squares structure in the denominator. - Rewrite negative exponents as reciprocals. - Interpret an exponent of \(0.5\) as a square root.

Solution

1. Combine the fractions in parentheses. Their common denominator is \((a^{-n}-b^{-n})(a^{-n}+b^{-n})\), and the numerator simplifies to \(2a^{-n}b^{-n}\). 2. Cancel the factor \(a^{-n}+b^{-n}\): \(A=\frac{2a^{-n}b^{-n}}{a^{-n}-b^{-n}}\). 3. Rewrite the negative exponents as reciprocals: \(A=\frac{\frac2{a^nb^n}}{\frac1{a^n}-\frac1{b^n}}=\frac2{b^n-a^n}\). 4. With \(a=4\), \(b=25\), and \(n=\frac12\), \(A=\frac2{\sqrt{25}-\sqrt4}=\frac23\).

Answer

The simplified expression is \(\frac2{b^n-a^n}\). Its value is \(\frac23\).
5250889
For \(x>0\), \(y>0\), and \(x\ne y\), simplify \(B=\left(\frac{x-y}{x^{\frac23}+x^{\frac13}y^{\frac13}+y^{\frac23}}+y^{\frac13}\right)x^{-\frac13}\).

Hints

- Rewrite \(x-y\) as a difference of cubes. - Use the factorization \(a^3-b^3=(a-b)(a^2+ab+b^2)\). - Simplify the expression in parentheses before multiplying by the outside factor. - Add exponents when multiplying powers with the same base.

Solution

1. View the numerator as a difference of cubes: \(x-y=(x^{\frac13})^3-(y^{\frac13})^3\). 2. Factor: \(x-y=(x^{\frac13}-y^{\frac13})(x^{\frac23}+x^{\frac13}y^{\frac13}+y^{\frac23})\). 3. Cancel the common factor in the fraction to obtain \(x^{\frac13}-y^{\frac13}\). 4. The expression in parentheses becomes \(x^{\frac13}-y^{\frac13}+y^{\frac13}=x^{\frac13}\). 5. Therefore \(B=x^{\frac13}x^{-\frac13}=x^0=1\).

Answer

\(1\)

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