Midpoint is a point that divides a line segment into two parts that are equal or congruent. It is a point that is equidistant between the two endpoints. It would be the point that is found halfway the two endpoints. So, we obtain this point by locating the point that is in between the two endpoints. We use the formula:
(x1+x2/2 , y1+y2/2)
For the problem above, we are given the midpoint and one of the endpoint and we locate the other point. We use the midpoint formula as follows:
x = x1+x2/2
-1.5 = -6 + x2 /2
x2 = 3
y = y1+y2/2
-1 = 5 + y2/2
y2 = -7
Therefore, the other endpoint would be at (3, -7).