Question

giải hệ 3x+2y=-1 và 2x+3y=-4

Answer 1

       \(\left\{{}\begin{matrix}3x+2y=-1\\2x+3y=-4\end{matrix}\right.\)

  \(\Leftrightarrow\left\{{}\begin{matrix}6x+4y=-2\\6x+9y=-12\end{matrix}\right.\)

  \(\Leftrightarrow\left\{{}\begin{matrix}-5y=10\\6x+4y=-2\end{matrix}\right.\)

  \(\Leftrightarrow\left\{{}\begin{matrix}y=-2\\6x+4.\left(-2\right)=-2\end{matrix}\right.\)

  \(\Leftrightarrow\left\{{}\begin{matrix}y=-2\\6x-8=-2\end{matrix}\right.\)

  \(\Leftrightarrow\left\{{}\begin{matrix}y=-2\\x=1\end{matrix}\right.\)