Question

1. what is the result of reflecting a point $(x,y)$ across the $y$-axis? $(-x,y)$ $(-y,x)$ $(x,-y)$ $(y,x)$

Explanation:

Step1: Recall reflection rule

When reflecting a point \((x,y)\) across the \(y -\)axis, the \(y -\)coordinate remains the same.
The \(x -\)coordinate changes its sign.
So the formula for reflection across the \(y -\)axis is \((x,y)\to(-x,y)\)

Answer:

\((-x,y)\)