Answer :

naǫ
The coordinates of the midpoint:
[tex](\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2})[/tex]
x₁,y₁ - the coordinates of one endpoint
x₂,y₂ - the coordinates of the other endpoint

[tex](-3,-7) \\ x_1=-3 \\ y_1=-7 \\ \\ (3,0) \\ x_2=3 \\ y_2=0 \\ \\ \frac{x_1+x_2}{2}=\frac{-3+3}{2}=\frac{0}{2}=0 \\ \\ \frac{y_1+y_2}{2}=\frac{-7+0}{2}=\frac{-7}{2}=-3.5 \\ \\ \boxed{(0,-3.5)} - \hbox{the midpoint}[/tex]
(0,3.5)

I hope this helps