xy - 7x + y = -22
=> x(y - 7) + y - 7 = -29
=> x(y - 7) + (y - 7) = -29
=> (x+1)(y - 7) = -29
ta có bảng :
| x+1 | -1 | 1 | -29 | 29 |
| y-7 | -29 | 29 | -1 | 1 |
| x | -2 | 0 | -30 | 28 |
| y | -22 | 36 | 6 | 8 |
\(xy-7x+y=-22\)
\(xy+y-7x=-22\)
\(y\left(x+1\right)-7x=-22\)
\(y\left(x+1\right)-7x-7=-22-7\)
\(y\left(x+1\right)-\left(7x+7\right)=-29\)
\(y\left(x+1\right)-7.\left(x+1\right)=-29\)
\(\left(y-7\right)-\left(x+1\right)=-29\)
Ta có bảng sau:
| y-7 | -29 | 1 | -1 | 29 |
| x+1 | 1 | -29 | 29 | -1 |
| y | -22 | 8 | 6 | 36 |
| x | 0 | -30 | 28 | -2 |
Vậy ....................................
