Reflection of a two dimensional figure in y-axis

On the screen, we see a triangle ABC in red color. Observe how the shape of the triangle A’’B’’C’’ (blue color) changes as we move the points A, B and C of the triangle ABC. Triangle A’’B’’C’’ is the reflection of the triangle ABC in the y-axis.
Questions to think about 1. What is the relation between the co-ordinates of A and A’’, B and B’’ and C and C’’? 2. Find where are the midpoints of AA’’, BB’’ and CC’’.