Đáp án:
a, `x^4y^4 + 64`
`= (x^4y^4 + 16x^2y^2 + 64) - 16x^2y^2`
`= (x^2y^2 + 8)^2 - (4xy)^2`
`= (x^2y^2 - 4xy + 8)(x^2y^2 + 4xy + 8)`
b, `324x^4 + 1`
`= (324x^4 + 36x^2 + 1) - 36x^2`
`= (18x^2 + 1)^2 - (6x)^2`
`= (18x^2 - 6x + 1)(18x^2 + 6x + 1)`
c, `x^8 + x^4 + 1`
`= (x^8 + 2x^4 + 1) - x^4`
`= (x^4 + 1)^2 - x^4`
`= (x^4 - x^2 + 1)(x^4 + x^2 + 1)`
d, `9x^3 - 13x + 6`
`= (9x^3 + 6x^2 - 9x) - (6x^2 + 4x - 6)`
`= 3x.(3x^2 + 2x - 3) - 2(3x^2 + 2x - 3)`
`= (3x - 2)(3x^2 + 2x - 3)`
Giải thích các bước giải: