Find the distance between the two x values: -10 to -7 is 3 units, so add to the midpoint: -7 + 3 = -4
The x value is -4
Now do the same for y:
7 to -3 is 10 units
Because the midpoint is less than the end point subtract:
Y = -3 -10 = -13
Y = -13
The endpoint would be (-4, -13)