Answer:
(x, y) → (−x, y)(x, y)
Explanation:
To do a transformation over the Y-axis, you just have to change the sign on the x in order to create a matching point on the other side of the Y axis, for example if you wish to make a reflection of the point (8,9), the reflection over the Y axis would be (-8,9), the same with X and Y, if you wish to make a reflection of (x,y) you just change the sign of the x like this: (-x,y)