The midpoint of fg is point h at (–5, 2). one endpoint is g(–9, –6). what is the y-coordinate of the other endpoint?

We are being asked to solve for the other endpoint especially for the y-coordinate of point F since the given line is FG where the midpoint is H (-5,2). The solution is shown below:
We have one end G (-9, -6)
We have midpoint H (-5,2)
midpoint of x = x1 +x2 / 2
                  -5 = x1 -9 /2 , cross multiply 2
                  -5 * 2 = x1 -9 , transpose -9 to the opposite side
                  -10 + 9 = x1, solve for x1
                           -1 = x1
midpoint of y = y1 + y2 / 2
                    2 = y1 -6 /2
                2*2 = y1 -6
                4+6 = y1
                   10 = y1 

The missing y-coordinate is equal to "10".