Đáp án:
x^5+x^4+1
= x^5 + x^4 + x^2 - x^2 + 1
= x^2 ( x^3 - 1 ) + ( x^4 + x^2 + 1 )
= x^2 ( x-1) (x^2+x+1) + (x^4 +2x^2+1-x^2)
= (x^3 - 1) (x^2+x+1) + [(x^2+1)^2 - x^2]
= (x^3-1) ( x^2+x+1) + (x^2+x+1) (x^2-x-1)
= (x^2 + x + 1) (x^3-1+x^2-x+1)
= (x^2 + x + 1) (x^3 + x^2 - x)
CHO CTLHN + 5 SAO!