Đáp án`+`Giải thích các bước giải:

`x-xy-y=0`

`<=>x-y(x+1)=0`

`<=>(x+1)-y(x+1)=1`

`<=>(x+1)(1-y)=1`

Bảng:

\begin{array}{|c|c|c|}\hline \text{x+1}&\text{1}&\text{-1}\\\hline \text{1-y}&\text{1}&\text{-1}\\\hline \text{x}&\text{0}&\text{-2}\\\hline \text{y}&\text{0}&\text{2}\\\hline\end{array}

Vậy `(x;y)=(0;0),(-2;2)`