a: Ta có: \(\left\{{}\begin{matrix}3x+2y=14\\5x+3y=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}15x+10y=70\\15x+9y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=67\\3x=14-2y=14-2\cdot67=-120\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-40\\y=67\end{matrix}\right.\)
b: Ta có: \(\left\{{}\begin{matrix}-x+2y-6=0\\5x-3y-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-x+2y=6\\5x-3y=5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-5x+10y=30\\5x-3y=5\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}7y=35\\2y-x=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=5\\y=4\end{matrix}\right.\)
