因式分解题大家帮帮我！（要过程，谢啦）

1,（x-y)(x*2+xy+y*2)+3xy(y-x)
=(x-y)(x^2-2xy+y^2)
=(x-y)^3

2,1+x+x(x+1)+x(x+1)*2+x(1+x)*3
=(x+1)[1+x+x(1+x)+x(1+x)^2]
=(x+1)(x+1)(1+x+x+x^2)
=(x+1)^4

3,4a*2b*2-(a*2+b*2-c*2)*2
=(2ab+a^2+b^2-c^2)(2ab+c^2-a^2-b^2)
=[(a+b)^2-c^2][c^2-(a-b)^2]
=(a+b+c)(a+b-c)(c+a-b)(c-a+b)

4,9(a-b)*2+12(a-b)+4
=[3(a-b)+2]^2
=(3a-3b+2)^2

5,a*n+2-4a*n+1+4a*n
=a^n(a^2-4a+4)
=a^n(a-2)^2

6,a(x*2=2xy)*2-ay*4
=a[(x^2-2xy)^2-y^4]
=a(x^2-2xy-y^2)(x^2-2xy+y^2)
=a(x+y-根号2*y)(x+y+根号2*y)(x-y)^2