Explanation:
When going from the preimage P to its image P', we multiply each coordinate by the scale factor 1/3.
To go in reverse (image to preimage), we multiply by the reciprocal of that scale factor. The reciprocal of 1/3 is 3/1 or simply 3.
Triple the coordinates of (-2, 5) to end up with (-6, 15)
We can check the answer by multiplying each coordinate of (-6, 15) by the original scale factor 1/3 and you should end up with (-2, 5) again.