The coordinates given are, P=(3,1) and Q=(-3,-7).
The midpoint of segment PQ is,
[tex](x,y)=(\frac{x_1+x_2_{}}{2},\text{ }\frac{y_1+y_2}{2})[/tex]Substitute the values in the midpoint formula,
[tex](x,y)=(\frac{3+(-3)}{2})\text{ , }(\frac{1+(-7)}{2})[/tex][tex](x,y)=(0,\frac{-6}{2})[/tex][tex](x,y)=(0,-3)[/tex]Thus the midpoint segment PQ is,
[tex](0,-3)[/tex]