\(\left[ \begin{array}{l}3x+y=5\\4x-y=9\end{array} \right.\)
⇔\(\left[ \begin{array}{l}7x=14 \\6+y=5\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=2\\x=-1\end{array} \right.\)
\(\left[ \begin{array}{l}2x+3y=-2\\3x-2y=-3\end{array} \right.\)
⇔\(\left[ \begin{array}{l}6x+9y=-6\\3x-2y=-3\end{array} \right.\)
⇔\(\left[ \begin{array}{l}13y=0 \\6x+0=-6 \end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=0\\x=-1\end{array} \right.\)
\(\left[ \begin{array}{l}5x-3(x+y)=10\\x+3y-6=9+2y\end{array} \right.\)
⇔\(\left[ \begin{array}{l}2x-3y=10\\9y−2=18+4y \end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=11\\x=4\end{array} \right.\)
