因式分解（难）(1)分解因式：x^2-2x-2y^2+4y-xy(2)分解因式：(x-2)^3-(y-2)^3-(x-y

(1)分解因式：x^2-2x-2y^2+4y-xy=(x+y)(x-2y)-2(x-2y)=(x+y-2)(x-2y)(2)分解因式：(x-2)^3-(y-2)^3-(x-y)^3=(x-y)[(x-2)^2+(x-2)(y-2)+(y-2)^2]-(x-y)^3=(x-y)[x^2-4x+4+xy-2x-2y+4+y^2-4y+4-x^2+2xy-y^2)=(x-y)(3xy-6x-6y+12)=3(x-y)(xy-2x-2y+4)=3(x-y)(x-2)(y-2)(3)分解因式：x^4+x^3-3x^2-4x-4=x^2(x^2+x-2)-(x^2+4x+4)=x^2(x+2)(x-1)-(x+2)^2=(x+2)(x^3-x^2-x-2)==(x+2)(x^3-2x^2+x^2-x-2)=(x+2)(x^2(x-2)+(x+1)(x-2))=(x+2)(x-2)(x^2+x+1)=(4)分解因式：x(x-1)+y(y+1)-2xy=x^2-2xy+y^2-(x-y)=(x-y-1)(x-y)(5)分解因式：x^3+5x^2+3x-9=x^3+3x^2+2x^2+3x-9=x^2(x+3)+(x+3)(2x-3)=(x+3)(x^2+2x-3)=(x+3)^2(x-1)(6)已知x^2+x-6是多项式2x^4+x^3-ax^2+bx+a+b-1的因式,求a.bx^2+x-6=0有两个解x=-3,x=2所以x^2+x-6是多项式2x^4+x^3-ax^2+bx+a+b-1的因式,所以x=-3,x=2也是2x^4+x^3-ax^2+bx+a+b-1=0的解代入后有32+8-4a+2b+a+b-1=0162-27-9a-3b+a+b-1=0b-a+13=04a+b-67=0a=16,b=3

1)分解因式：x^2-2x-2y^2+4y-xy=(x-2y)(x+y)-2(x-2y)=(x-2y)(x+y-2)(2)分解因式：(x-2)^3-(y-2)^3-(x-y)^3=(x-2-y+2)[(x-2)^2+(x-2)(y-2)+(y-2)^2]-(x-y)^3=(x-y)(x^2-4x+4+xy-2x-2y+4+y^2-4y+4)-(x-y)^3=(x-y)(x^2-6x+y^2-6y+...

(1) x^2-xy-2y^2-2x+4y=(x-2y)(x+y)-2(x-2y) =（x-2y)(x+y-2)(2)(x-2-y+2)[x^2+(x-2)(y-2)+y^2]-(x-y)^3=(x-y)[x^2+xy-2x-2y+4+y^2-(x-y)^2]=(x-y)(3xy-2x-2y+4)(3)x^4+x^3-2x^2-(x^2+4x+4)=x^2(x+2)(x-1)-(x+...