Answer:
Reflect over the y-axis
Step-by-step explanation:
When you reflect a point across the y-axis, the y-coordinate remains the same, but the x-coordinate is transformed into its opposite (its sign is changed).
Notice that B is 5 horizontal units to the right of the y-axis, and B' is 5 horizontal units to the left of the y-axis.
The reflection of the point (x,y) across
the y-axis is the point (-x,y).
