Respuesta :
[tex]\bf ~~~~~~~~~~~~\textit{middle point of 2 points }\\ \quad \\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~{{ -11}} &,&{{ 4}}~)
% (c,d)
&&(~{{ -1}} &,&{{ -9}}~)
\end{array}\qquad
% coordinates of midpoint
\left(\cfrac{{{ x_2}} + {{ x_1}}}{2}\quad ,\quad \cfrac{{{ y_2}} + {{ y_1}}}{2} \right)
\\\\\\
\left( \cfrac{-1-11}{2}~~,~~\cfrac{-9+4}{2} \right)\implies \left(-6~~,~~-\frac{5}{2} \right)\implies \left( -6,~~-2\frac{1}{2} \right)[/tex]
