[tex]\bf ~~~~~~~~~~~~\textit{middle point of 2 points }\\\\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~ 7 &,& 5~)
% (c,d)
&&(~ 7 &,& 11~)
\end{array}\qquad
% coordinates of midpoint
\left(\cfrac{ x_2 + x_1}{2}\quad ,\quad \cfrac{ y_2 + y_1}{2} \right)
\\\\\\
\left( \cfrac{7+7}{2}~~,~~\cfrac{11+5}{2} \right)\implies \left( \cfrac{14}{2}~~,~~\cfrac{16}{2} \right)\implies (7~,~8)[/tex]
