the midpoint of the line having the endpoints [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex] is [tex](\frac{x_{1}+_x_{2}}{2}, \frac{y_{1}+_y_{2}}{2})[/tex]
basically average them
so given that the line has the endpoints of (-3,7) and (9,-2)
x₁=-3
y₁=7
x₂=9
y₂=-2
so the midpoint can be found by doing
[tex](\frac{-3+9}{2}, \frac{7+(-2)}{2})=[/tex]
[tex](\frac{6}{2}, \frac{7-2}{2})=[/tex]
[tex](3, \frac{5}{2})[/tex]
the midpoint is [tex](3,\frac{5}{2})[/tex]
