Answer:
When we reflect over the y-axis, sign of the x-coordinate changes.
Explanation:
Since we know when we'll reflect over y-axis, y-axis will work as a mirror. Y-coordinates will remain same but the only change that happens to any point on the graph is x coordinates.
In second quadrant x-coordinates are negative and in first quadrant positive, while y coordinates are positive in both first and second quadrant. So if we will reflect from first to second or second to first quadrant y-coordinates will remain same but x-coordinates will change..
In third quadrant x-coordinates are negative and in fourth positive, while y coordinates are negative in both third and fourth quadrant. So if we will reflect from third to fourth or fourth to third quadrant y-coordinates will remain same but x-coordinates will change.
Therefore, from above explanation we can conclude that when we reflect over the y-axis, sign of the x-coordinate changes.