Đáp án+Giải thích các bước giải:
`c) x^3-3x^2+3x-1-y^3`
`=( x^3-3x^2+3x-1)-y^3`
`=(x-1)^3-y^3`
`=[(x-1)-y].[(x-1)^2+y.(x-1)+y^2]`
`=(x-y-1).(x^2-2x+1+xy-y+y^2)`
`d) 5x^3-3x^2y-45xy^2+27y^3`
`=(5x^3-3x^2y)-(45xy^2-27y^3)`
`=x^2(5x-3y)-9y^2(5x-3y)`
`=(x^2-9y^2)(5x-3y)`
`=(x-3y)(x+3y)(5x-3y)`
`e) 3x^2(a-b+c)+36xy(a-b+c)+108y^2(a-b+c)`
`=(a-b+c)(3x^2+36xy+108y^2)`
`=3(a-b+c)(x^2+12xy+36y^2)`
`=3(a-b+c)(x+6y)^2`
