Question

When this matrix is multiplied by the points of a figure, the new points will be a reflection over which axis or line?

Answer 1

x-axis y-axis

Answer 2

To find the symmetry axis, solve
\[\left[\begin{matrix}-1 & 0 \\ 0 & 1\end{matrix}\right]\left(\begin{matrix}x \\ y\end{matrix}\right)=\left(\begin{matrix}x \\ y\end{matrix}\right)\]

The solution to this equation gives you any point that is mapped into itself, i.e. any point on the symmetry axis.

Answer 3

Well (1, 0; 0,-1) would be x-axis so I'm guessing y-axis.

Answer 4

x axis