Answer:
H(-1, -1)
Explanation:
The easiest way to do this is to graph the three points you are given. Then you can see where the 4th point needs to be to form a rectangle, and you can find its coordinates.
Plot points E, F, and G or a coordinate plane.
You will see that the points are at bottom left, top left, and top right forming a rectangle. The missing point is bottom right.
The coordinates of point H are (-1, -1)