Question

The notation (x,y)→(−x,y) means a reflection across the y axis.

Answer 1

This is true.

Explanation:

To prove this as true what we can do is draw a graph. On one of the graphs, we will have a point at (-7,1). If we were going to reflect it over the y-axis by counting the distance it is from the y-axis and counting it in the other direction. When we do this we get a point of (7,1). We can infer that because it was flipped in the y-axis the y value stayed the same while the x-axis changed.

This is how we can prove this to be true.