Numeric Reasoning>Using Arrays and Matrices to Solve Applied Problems Including Transformations(TEKS.AQR.9-12.2.F) Practice Test

Austin theater crew resizes a triangular stage backdrop with vertices (−2,1), (1,1), (0,−2). The backdrop is dilated about the origin by scale factor k = 1.5 using $D = \begin{bmatrix}1.5 & 0 \\ 0 & 1.5\end{bmatrix}$. What are the new vertex coordinates, and what does this mean for the backdrop's dimensions?

For a floor plan sketch, a rectangle with vertices (−4,2), (−1,2), (−1,−1), (−4,−1) is reflected across the $y$-axis using $M=\begin{bmatrix}-1 & 0 \\ 0 & 1\end{bmatrix}$. What are the new coordinates, and what does this reflection do?