Step 1: Concept
To transform a triangle over y = x, the point of the reflection will be
Point of pre-image Point of image
(x, y) (y, x)
For example, if the vertice of the pre-image is (3,2), then the vertice of the image will be (2,3) when reflected over y = x, meaning you will just swap the coordinate.
Step 2:
The coordinate of the vertices of the pre-image of a triangle PQR is P(-5,1), Q(-3,-2), and R(-4,-3). When reflected over y = x, the coordinate of the image will be:
P (1, -5) , Q (-2 , -3) and R (-3 , -4)
Step 3:
Final answer
The vertices of P reflected over y = x is P' (1, -5)
Answer P' (1, -5)