## College Algebra (6th Edition)

$BZ=\left[\begin{array}{l} -x\\ y \end{array}\right]$ $(x,y)\mapsto(-x,y)$ is a reflection about the y-axis.
$CZ=\left[\begin{array}{ll} -1 & 0\\ 0 & 1 \end{array}\right]\left[\begin{array}{l} x\\ y \end{array}\right]=\left[\begin{array}{l} -1(x)+0y\\ 0x+1(y) \end{array}\right]=\left[\begin{array}{l} -x\\ y \end{array}\right]$ If the point (x,y) is transformed into ($-x,y$), it has been reflected about the y-axis. Reflecting all vertices about the y-axis results in reflecting the graphic about the y-axis.