[tex]\bf ~~~~~~~~~~~~\textit{middle point of 2 points } \\\\ (\stackrel{x_1}{1}~,~\stackrel{y_1}{9})\qquad (\stackrel{x_2}{-3}~,~\stackrel{y_2}{5}) \qquad \left(\cfrac{ x_2 + x_1}{2}~~~ ,~~~ \cfrac{ y_2 + y_1}{2} \right) \\\\\\ \left(\cfrac{-3+1}{2}~~,~~\cfrac{5+9}{2} \right)\implies \left(\cfrac{-2}{2}~~,~~\cfrac{14}{2} \right)\implies (-1~~,~~7)[/tex]
