Câu 2:
$\left\{\begin{matrix}4x+2=-y-3\\-3x+2=12\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}4x+y=-3-2\\2y=12+3x\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}4x+y=-5\\y=\dfrac{12+3x}{2}\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}4x+\dfrac{12+3x}{2}=-5\\y=\dfrac{12+3x}{2}\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}8x+12+3x=-10\\y=\dfrac{12+3x}{2}\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}11x=-22\\y=\dfrac{12+3x}{2}\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}x=-2\\y=\dfrac{12+3x}{2}\end{matrix}\right.$
\Leftrightarrow $\left\{\begin{matrix}x=-2\\y=3\end{matrix}\right.$