\(\left\{{}\begin{matrix}2x+3y=2\\x+2y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x+3y=2\\2x+4y=6\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}2x+3y-2x-4y=2-6\\x+2y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-y=-4\\x=3-2y\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}y=4\\x=3-2\cdot4=3-8=-5\end{matrix}\right.\)
\(\left\{{}\begin{matrix}2x+3y=2\\x+2y=3\end{matrix}\right.\)
`<=>` \(\left\{{}\begin{matrix}2x+3y=2\\x=3-2y\end{matrix}\right.\) `<=>` \(\left\{{}\begin{matrix}2\left(3-2y\right)+3y=2\\x=3-2y\end{matrix}\right.\)
`<=>` \(\left\{{}\begin{matrix}6-4y+3y=2\\x=3-2y\end{matrix}\right.\) `<=>` \(\left\{{}\begin{matrix}-y=-4\\x=3-2y\end{matrix}\right.\)
`<=>` \(\left\{{}\begin{matrix}y=4\\x=3-2.4\end{matrix}\right.\) `<=>` \(\left\{{}\begin{matrix}y=4\\x=-5\end{matrix}\right.\)
Vậy hệ phương trình có nghiệm `(x;y)=(-5;4)`
