EXPLANATION :
From the problem, we have segment GH and the midpoint is M(-2, 5).
One of the endpoints has coordinates of H(-3, 7)
and we need to find the coordinates of G(x, y)
The midpoint formula is :

where (x1, y1) are the coordinates of G
(x2, y2) = (-3, 7) are the coordinates of H
and (-2, 5) are the coordinates of the midpoint.
Then :

We can equate the x coordinate :

then the y coordinate :

Now we have the point (-1, 3)
ANSWER :
The coordinates of the other endpoint are G(-1, 3)