[tex]\bf ~~~~~~~~~~~~\textit{middle point of 2 points }
\\\\
S(\stackrel{x_1}{x}~,~\stackrel{y_1}{y})\qquad
T(\stackrel{x_2}{0}~,~\stackrel{y_2}{3})
\qquad
\left(\cfrac{ x_2 + x_1}{2}~~~ ,~~~ \cfrac{ y_2 + y_1}{2} \right)
\\\\\\
\left( \cfrac{0+x}{2}~~,~~\cfrac{3+y}{2} \right)=\stackrel{midpoint}{(5,-8)}\implies
\begin{cases}
\cfrac{0+x}{2}=5\\[0.8em]
\boxed{x=10}\\[-0.5em]
\hrulefill\\
\cfrac{3+y}{2}=-8\\[0.8em]
3+y=-16\\
\boxed{y=-19}
\end{cases}[/tex]
