We can find the coordinates of the midpoint calculating the average between the coordinates of both points.
If we have P1=(7, 5) and P2=(3, 1), the coordinates of the midpoint are:
[tex]\begin{gathered} x=\frac{x_1+x_2}{2}=\frac{7+3}{2}=\frac{10}{2}=5 \\ \\ y=\frac{y_1+y_2}{2}=\frac{5+1}{2}=\frac{6}{2}=3 \end{gathered}[/tex]The midpoint is (5, 3).