[tex]\bf ~~~~~~~~~~~~\textit{middle point of 2 points }
\\\\
(\stackrel{x_1}{-5.5}~,~\stackrel{y_1}{-6.1})\qquad
(\stackrel{x_2}{-0.5}~,~\stackrel{y_2}{9.1})
\qquad
% coordinates of midpoint
\left(\cfrac{ x_2 + x_1}{2}~~~ ,~~~ \cfrac{ y_2 + y_1}{2} \right)
\\\\\\
\left( \cfrac{-0.5-5.5}{2}~~,~~\cfrac{9.1-6.1}{2} \right)\implies \left( \cfrac{-6}{2}~~,~~\cfrac{3}{2} \right)\implies \left(-3~,~1\frac{1}{2} \right)[/tex]
