Tìm x, y biết 2x + 3y -xy = 8

`2x + 3y -xy = 8`

`=>x(2-y)=8-3y`

`=>x(2-y)=2+6-3y`

`=>x(2-y)=2+3(2-y)`

`=>x(2-y)-3(2-y)=2`

`=>(2-y)(x-3)=2`

Ta có bảng sau :

\begin{array}{|l|r|} \hline x-3&1&2&-1&-2\\ \hline 2-y&2&1&-2&-1\\ \hline x&4&5&2&1 \\ \hline y&0&1&4&3 \\ \hline \end{array}

Vậy `...`