9道因式分解题
问题描述：
9道因式分解题
1.(x+y)^3+2xy(1-x-y)-1
2.x^3+x^2-2004*2005x
3.(x^2-x-6)(x^2+3x-4)+24
4.x^6+15x^3y+50y^2
5.（x^2+4x+6）+(x^2+6x+6)+x^2
6.(x-3)(x+4)(x-5)(x+6)+80
7.x^3-7x+6
8.x^4+y^4+(x+y)^4
9.xy(xy+1)+(xy+3)-2(x+y+1/2)-(x+y-1)^2
答
1）(x+y)^3+2xy(1-x-y)-1立方差公式：a³-b³=(a-b)(a²+ab+b²)(x+y)^3+2xy(1-x-y)-1=[(x+y)³-1]-2xy(x+y-1)=(x+y-1)[(x+y)²+(x+y)+1]- 2xy(x+y-1)=(x+y-1)(x²+y²+x+y+1)2）x^...