a, xy=5 b, xy-8=0 Tìm x,y € Z

Giải thích các bước giải:

`a)`

`xy = 5`

`=> xy ∈ Ư(5)`

\begin{array}{|c|c|c|}\hline \text{x}&\text{-1}&\text{1}&\text{-5}&\text{5}\\\hline \text{y}&\text{-5}&\text{5}&\text{-1}&\text{1}\\\hline\end{array}

`b)`

`xy - 8 = 0`

`xy = 0 + 8`

`xy = 8`

`=> xy ∈ Ư(8)`

\begin{array}{|c|c|c|}\hline \text{x}&\text{-1}&\text{-2}&\text{-4}&\text{-8}&\text{1}&\text{2}&\text{4}&\text{8}\\\hline \text{y}&\text{-8}&\text{-4}&\text{-2}&\text{-1}&\text{8}&\text{4}&\text{2}&\text{1}\\\hline\end{array}

$@Thanh$