(1)4a^3-4a²+4a=4a(a²-a+1)
(2)a^3+ab²-2a²b=a(a²-2ab+b²)=a(a-b)²
(3)-x^3+2x²-x=-x(x²-2x+1)=-x(x-1)²
(4)xy²-2xy+2y-4=(xy²-2xy)+(2y-4)=xy(y-2)+2(y-2)=(y-2)(xy+2)
(5)a²b-2ab²+b^3=b(a²-2ab+b²)=b(a-b)²
(6)x²-y²-3y-3不好分解因式
(7)a²-b²-2b-1=a²-(b²+2b+1)=a²-(b+1)²=(a+b+1)(a-b-1)