Question

giupspppppppppppppppppppppp ạ

Answer 1

3) Thay m=2 vào hệ phương trình, ta được:

\(\left\{{}\begin{matrix}x-2y=2-4\cdot2=2-8=-6\\2x+y=3\cdot2+1=7\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x-2y=-6\\2x+y=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x-4y=-12\\2x+y=7\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}-5y=-19\\2x+y=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{19}{5}\\y=7-2x=\dfrac{-3}{5}\end{matrix}\right.\)