x3 - 6x2 + 12x - 8
= x3 - 2x2 - 4x2 + 4x + 8x - 8
= (x3 - 2x2) - (4x2 - 8x) + (4x - 8)
= x2.(x - 2) + 4x.(x - 2) + 4.(x - 2)
= (x - 2).(x2 + 4x + 4)
= (x - 2).(x2 + 2x + 2x + 4)
= (x - 2).[x.(x + 2) + 2.(x + 2)]
= (x - 2).(x + 2).(x + 2)
= (x - 2).(x + 2)2
những bạn nhầm đề bài r bạn
x^3+y^3+6x^2+12x+8
=(x^3+6x^2+12x+8)+y^3
=(x+2)^3+y^3
=(x+2+y).(x^2+4x+4+y^2-xy-2y)