Question

4 người nhanh nhất vote 5* nha

Answer 1

`x-y=-4<=>x=y-4`

`=>(x-7)/(y+5)=(y-4-7)/(y+5)=(y-11)/(y+5)`

`=>(y-11)/(y+5)=7/6`

`=>6(y-11)=7(y+5)`

`=>6y-66=7y+35`

`=>y=-101`

`=>x=y-4=-105`

Vậy `(x,y)=(-105,-101)`

Làm gì có sao đâu mà vote 5* :))

Answer 2

\(\dfrac{x-7}{y+5}=\dfrac{7}{6}\)

\(\Leftrightarrow\dfrac{x-7}{7}=\dfrac{y+5}{6}=\dfrac{x-7-y-5}{7-6}=\dfrac{-4-12}{1}=-16\)

\(\Leftrightarrow\left\{{}\begin{matrix}x-7=7\cdot\left(-16\right)\\y+5=6\cdot\left(-16\right)\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=-105\\y=-101\end{matrix}\right.\)

Answer 3

\(\dfrac{x-7}{5+y}=\dfrac{7}{6}\)

\(\Rightarrow\) \(6.\left(x-7\right)=7.\left(5+y\right)=6x-42=35+7y\)

\(\Rightarrow\) \(6x-7y=35+42=77\)

Mà \(x=y-4\) 

Vậy, ta có: \(6y-24-7y=-y-24=77\) 

\(\Rightarrow-y=77+24=101\)

\(\Rightarrow y=-101\)

\(\Rightarrow x=-101+\left(-4\right)=-105\)