a) \(\left\{{}\begin{matrix}4x+y=-5\\3x-2y=-12\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}12x+3y=-15\\12x-8y=-48\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}11y=33\\4x+y=-5\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=-2\\y=3\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x+3y=4y-x+5\\2x-y=3x-2\left(y+1\right)\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}2x-y=5\\x-y=2\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x-y=2\\x=3\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=3\\y=1\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\sqrt{3}x-2\sqrt{2}y=7\\\sqrt{2}x+3\sqrt{3}y=-2\sqrt{6}\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}\sqrt{6}x-4y=7\sqrt{2}\\\sqrt{6}x+9y=-6\sqrt{2}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}13y=-13\sqrt{2}\\\sqrt{3}x-2\sqrt{2}y=7\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=\sqrt{3}\\y=-\sqrt{2}\end{matrix}\right.\)
