Hướng dẫn trả lời:
a) `x^2y + x^2y^2 - xy^2.`
`= xy.x + xy.xy - xy.y.`
`= xy.(x + xy - y).`
b) `3xy - 6y + x^2 - 2x.`
`= 3y.(x - 2) + x.(x - 2).`
`= (3y + x).(x - 2).`
c) `x^2 - 12x + 36 - 64y^2.`
`= (x^2 - 12x + 36) - 64y^2.`
`= (x^2 - 2.x.6 + 6^2) - 64y^2.`
`= (x - 6)^2 - (8y)^2.`
`= [(x - 6) + 8y].[(x - 6) - 8y].`
`= (x + 8y - 6).(x - 8y - 6).`
d) `x^2 + 7x + 10.`
`= x^2 + 5x + 2x + 10.`
`= (x^2 + 5x) + (2x + 10).`
`= x.(x + 5) + 2.(x + 5).`
`= (x + 2).(x + 5).`
Đáp án:
a) `= xy.(x + xy - y).`
b) `= (3y + x).(x - 2).`
c) `= (x + 8y - 6).(x - 8y - 6).`
d) `= (x + 2).(x + 5).`
