Hướng dẫn trả lời:
a) `x^3y - 2x^2y^2 + 5xy`
`= xycdotx^2 + xycdot(- 2xy) + xycdot5`
`= xycdot(x^2 - 2xy + 5)`
b) `2x^2cdot(x + 1) + 4xcdot(x + 1)`
`= (2x^2 + 4x)cdot(x + 1)`
`= (2xcdotx + 2xcdot2)cdot(x + 1)`
`= 2xcdot(x + 2)cdot(x + 1)`
c) `2/5xcdot(y - 1) - 2/5ycdot(1 - y)`
`= 2/5xcdot(y - 1) - 2/5ycdot[- (y - 1)]`
`= 2/5xcdot(y - 1) + 2/5ycdot(y - 1)`
`= (2/5x + 2/5y)cdot(y - 1)`
`= 2/5cdot(x + y)cdot(y - 1)`
Đáp án:
a) `= xycdot(x^2 - 2xy + 5)`
b) `= 2xcdot(x + 2)cdot(x + 1)`
c) `= 2/5cdot(x + y)cdot(y - 1)`