Question

[Duong Thi Nhuong TH Hoa Trach - Pho...]

Giải: 

a) \(\hept{\begin{matrix}2x-3y=1\\4x-5y=2\end{matrix}}\)

b) \(\hept{\begin{matrix}\left(x+1\right)\left(y+1\right)=8\\x\left(x+1\right)+y\left(y+1\right)+xy=17\end{matrix}}\)

Answer 1

[Trần Hữu Ngọc Minh]

a)\(\hept{\begin{cases}2x-3y=1\\4x-5y=2\end{cases}\Leftrightarrow\hept{\begin{cases}4x-6y=2\\4x-5y=2\end{cases}}}\)

Trừ 2 vế lại ta được 

\(4x-4x-6y+5y=0\Leftrightarrow-y=0\Leftrightarrow y=0\)

\(\Rightarrow x=\frac{1}{2}\)