[tex]\bf \textit{middle point of 2 points }\\ \quad \\
\begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
A&({{ -3}}\quad ,&{{ 0}})\quad
% (c,d)
B&({{ c}}\quad ,&{{ d}})
\end{array}\qquad
% coordinates of midpoint
\left(\cfrac{{{ x_2}} + {{ x_1}}}{2}\quad ,\quad \cfrac{{{ y_2}} + {{ y_1}}}{2} \right)[/tex]
[tex]\bf midpoint\implies \left( \cfrac{c-3}{2},\cfrac{d+0}{2} \right)=(2,3)\implies
\begin{cases}
\cfrac{c-3}{2}=2\\\\
\cfrac{d+0}{2}=3
\end{cases}
\\\\\\
\cfrac{c-3}{2}=2\implies c-3=4\implies \boxed{c=7}
\\\\\\
\cfrac{d}{2}=3\implies \boxed{d=6}[/tex]
