Gọi $M_1;M2_2;M_3$ lần lượt là ${D_{Ox}}\left( M \right),\,{D_{Oy}}\left( M \right),{D_O}\left( M \right)$
$\begin{array}{l}
M\left( {x;y} \right)\\
\Rightarrow {D_{Ox}}\left[ {M\left( {x;y} \right)} \right] = {M_1}\left( {{x_1};{y_1}} \right)\\
\Rightarrow \left\{ \begin{array}{l}
{x_1} = x\\
{y_1} = - y
\end{array} \right.\\
\Rightarrow M\left( { - 2; - 3} \right)\\
{D_{Oy}}\left[ {M\left( {x;y} \right)} \right] = {M_2}\left( {{x_2};{y_2}} \right)\\
\Rightarrow \left\{ \begin{array}{l}
{x_2} = - x\\
{y_2} = y
\end{array} \right.\\
\Rightarrow {M_2}\left( {2;3} \right)\\
{D_O}\left( M \right) = {M_3}\left( {{x_3};{y_3}} \right)\\
\Rightarrow \left\{ \begin{array}{l}
\dfrac{{{x_3} - 2}}{2} = 0\\
\dfrac{{{y_3} + 3}}{2} = 0
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
{x_3} = 2\\
{y_3} = - 3
\end{array} \right.\\
\Rightarrow {M_3}\left( {2; - 3} \right)
\end{array}$
