The midpoint of mn is point p at (-4,6). if point m is at (8,-2), what are the coordinates of point n?

x₁ + x₂                             y₁ + y₂
    2      = M                        2     = M

x + 8                                 y + -2
   2    = -4                            2           =6
multiply both sides by 2.

x+8=-8                             y - 2 = 12
x = -16                             y = 14

Final  (-16, 14)

The midpoint of 2 points is basicaly the average of th points

so
(x1,y1) and (x2,y2)
the midpoint x value is (x1+x2)/2
midpoint y value is (y1+y2)/2

so

midpoint is (-4,6)
a point i (8,-2)
so then
the missing point is (x2,y2)
so
(x2+8)/2=-4
x2+8=-8
x2=-16

(y2-2)/2=6
y2-2=12
y2=14

the point n is (-16,14)

The answer for this question is 80