Plug the three points -- (7, -4), (8, 5), and (x, y) -- into the Midpoint Formula, and solve for x and y, like is shown here....suppose that P is an endpoint of a segment PQ and M is the midpoint of PQ. Find the coordinates of endpoint Q. I have a few problems like this to do. Heres the first one. P (7,-4) and M (8,5). How do I solve these?