Х^8+х^4+1

a^3-3a+2

х^4+х^2 у^2+у^4

1) x^8+x^4+1 = (x^8+2x^4+1) - x^4 = (x^4+1) ^2 - (x^2) ^2 = (x^4-x^2+1) (x^4+x^2+1) =

= (x^4-x^2+1) ((x^2+1) ^2-x^2) = (x^4-x^2+1) ((x^2-x+1) (x^2+x+1)

2) (a-1) ^2 (a+2) = a (a^2-3) + 2 = (a-1) ^3+3 (a-1) ^2

3) x^2 (x^2+y^2) + y^4=x^4+y^2 (x^2+y^2) = (x^2-x y+y^2) (x^2+x y+y^2)