Ta có: $4\overrightarrow{IJ}=2\left( \overrightarrow{IQ}+\overrightarrow{IN} \right)$

Mà $\overrightarrow{IM}+\overrightarrow{IP}=\overrightarrow{0}$ do đó $\overrightarrow{IQ}+\overrightarrow{IN}=\overrightarrow{IM}+\overrightarrow{MQ}+\overrightarrow{IP}+\overrightarrow{PN}=\overrightarrow{MQ}+\overrightarrow{PN}$

$=\frac{1}{2}\left( \overrightarrow{AE}+\overrightarrow{BD} \right)+\frac{1}{2}\overrightarrow{DB}=\frac{1}{2}\overrightarrow{AE}$

Suy ra $4\overrightarrow{IJ}=\overrightarrow{AE}\Leftrightarrow \left\{ \begin{align}   & 4\left( 0-1 \right)=4-{{x}_{A}} \\  & 4\left( 2+1 \right)=5-{{y}_{A}} \\ \end{align} \right.$$\Leftrightarrow \left\{ \begin{align}  & {{x}_{A}}=8 \\  & {{y}_{A}}=-7 \\ \end{align} \right.$