Hướng dẫn trả lời:
Bài 5:
a) `4x^2 - 6x`
`= 2xcdot2x - 2xcdot3`
`= 2xcdot(2x - 3)`
b) `x^3y - 2x^2y^2 + 5xy`
`= xycdotx^2 - xycdot2xy + xycdot5`
`= xycdot(x^2 - 2xy + 5)`
c) `2x^2cdot(x + 1) + 4xcdot(x + 1)`
`= (2x^2 + 4x)cdot(x + 1)`
`= 2xcdot(x + 2)cdot(x + 1)`
d) `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) `= 2xcdot(2x - 3)`
b) `= xycdot(x^2 - 2xy + 5)`
c) `= 2xcdot(x + 2)cdot(x + 1)`
d) `= 2/5cdot(x + y)cdot(y - 1)`
