51319110
The line \(s\) is given by \(s(x) = \frac{2}{3}x + 5\).
1. Reflect \(s\) across the y-axis. Call the image \(t\) and write its equation.
2. Reflect \(t\) across the x-axis. Call the new image \(u\) and write its equation.
3. Compare \(s\) and \(u\). What single rigid motion maps \(s\) directly to \(u\)?
Hints
- Apply the two reflections in order and track which coordinate sign changes each time.
- Compare the original equation with the final equation.
- Which single transformation changes both \(x\) and \(y\) to their opposites?
Solution
1. Reflecting across the y-axis replaces \(x\) with \(-x\), so \(t(x) = -\frac{2}{3}x + 5\).
2. Reflecting across the x-axis multiplies all outputs by \(-1\), so \(u(x) = \frac{2}{3}x - 5\).
3. Reflecting across both coordinate axes is equivalent to a \(180^\circ\) rotation about the origin. That rotation maps \(s\) directly to \(u\).
Answer
1. \(t(x) = -\frac{2}{3}x + 5\)
2. \(u(x) = \frac{2}{3}x - 5\)
3. A \(180^\circ\) rotation about the origin
