有分.
问题描述：
有分.
(1)x^3+2y-x-2x^2y.
(2)x^3-2x+1.
(3)x^3+3x^2+3x+2.
(4)x^4-7x^2+9.
(5)x^2+4xy-4y^2.(用求根法.)
答
1.原式=x^2(x-2y)-(x-2y)=(x^2-1)(x-2y)=(x+1)(x-1)(x-2y)2.原式=x^3-x^2+x^2-2x+1=x^2(x-1)+(x-1)^2=(x-1)(x^2+x-1)3.原式=x^3+2x^2+x^2+3x+2=x^2(x+2)+(x+2)(x+1)=（x^2+x+1)(x+2)4.原式=x^4-6x^2+9-x^2=(x^2-3)^2...