\(\left\{{}\begin{matrix}\left|x-2\right|+2\left|y-1\right|=9\\x+\left|y-1\right|=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\left|x-2\right|-2\left(x+1\right)=9\\\left|y-1\right|=-\left(x+1\right)\end{matrix}\right.\)
Vì | y - 1 | ≥ 0 nên x ≤ - 1 ⇒ x - 2 < 0
⇒ | x - 2 | = 2 - x
\(\Rightarrow\left\{{}\begin{matrix}2-x-2x-2=9\\\left|y-1\right|=-\left(x+1\right)\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-3\\\left|y-1\right|=2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=-3\\\left[{}\begin{matrix}y-1=2\\1-y=2\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-3\\\left[{}\begin{matrix}y=3\\y=-1\end{matrix}\right.\end{matrix}\right.\)
