多项式分解因式 1,x^2-y^2-3x+3y 2 ,(x-y)^2+4xy 3 ,x^2y+4y(x-3)
问题描述：
多项式分解因式 1,x^2-y^2-3x+3y 2 ,(x-y)^2+4xy 3 ,x^2y+4y(x-3)
答
x^2-y^2-3x+3y
＝（x^2-y^2）-(3x-3y)
=(x+y)(x-y)-3(x-y)
=(x+y-3)(x-y)
(x-y)^2+4xy
=x^2-2xy+y^2+4xy
=x^2+2xy+y^2
=(x+y)^2
x^2y+4y(x-3)
=y(x^2+4x-12)
=y(x+6)(x-2)
答
1.(x+y-3)(x-y)
2.(x+y)^2
3.y(x+6)(x-2)
答
（x-y）(x+y-1)
(x+y)^2
y(x+6)(x-2)