Answer:
Q' (-2, 2)
P' (-2, 7)
R' (6, 2)
Explanation:
When reflecting over a diagnal line such as y = x or y = -x, a trick is to count the boxes at an angle to see how many spaces it is away from the line. Be sure to recipicate what you counted the first time, and when reflecting over y = -x, flip the x and y coordinates and if needed, change the signs.
Hope this helps!