Gọi \(M' = {D_I}\left( M \right)\), khi đó \(\left\{ \begin{array}{l}x' = 2{x_I} - x\\y' = 2{y_I} - y\end{array} \right.\)\( \Rightarrow \left\{ \begin{array}{l}x' = 2.1 - 3 = - 1\\y' = 2.2 - \left( { - 1} \right) = 5\end{array} \right.\) hay \(M'\left( { - 1;5} \right)\).
Chọn B.
