@Ta lét
Bài làm :
`(a+b-1)×(b+2)=2`
Ta có các trường hợp sau :
`2 = 1 . 2 = -1 . -2 = 2 . 1 = -2 . -1`
→ Ta có bảng sau :
$\begin{array}{|c|c|}\hline\text{a + b - 1}&\text{1}&\text{-1}&\text{2}&\text{-2}\\\hline \text{b + 2}& \text{2}&\text{-2}&\text{1}&\text{-1}\\\hline \text{a}&\text{2}&\text{4}&\text{4}&\text{2}\\\hline \text{b}&\text{0}&\text{-4}&\text{-1}&\text{-3}\\\hline\end{array}$
Vậy `(a;b) = {(2;0),(4;-4),(4;-1),(2;-3)}`
