calculate midpoint between A(1.-2) and C(5,9)

$$\left(\frac{1+5}{2},\frac{-2+9}{2}\right)\\\\ =\left(\frac{6}{2},\frac{7}{2}\right)\\\\ =(3,3.5)$$

$${\frac{\left(\begin{pmatrix} {\mathtt{1}} \\ -{\mathtt{2}} \end{pmatrix} {\mathtt{\,\small\textbf+\,}}\begin{pmatrix} {\mathtt{5}} \\ {\mathtt{9}} \end{pmatrix} \right)}{{\mathtt{2}}}} = \begin{pmatrix} {\mathtt{3}} \\ {\mathtt{3.5}} \end{pmatrix}$$