Question

mng giải hẳn ra giúp mik ạ

Answer 1

Lời giải:

HPT \(\Leftrightarrow \left\{\begin{matrix} xy+4x-5y-20=xy+x-4y-4\\ xy-3x+y-3=xy-2x-y+2\end{matrix}\right.\)

\( \Leftrightarrow \left\{\begin{matrix} 3x-y=16\\ -x+2y=5\end{matrix}\right.\Leftrightarrow \left\{\begin{matrix} x=\frac{37}{5}\\ y=\frac{31}{5}\end{matrix}\right.\)

Khi đó: \(m+2n=\frac{37}{5}+2.\frac{31}{5}=\frac{99}{5}\)