3x^2y-6xy^2+3y^3分解因式

3x^2y-6xy^2+3y^3
=3y*(x^2-2xy+y^2)
=3y*(x-y)^2

3x²y-6xy²+3y³=3x²y-3xy²-（3xy²-3y³）=3xy(x-y)-3y²(x-y)=3y(x-y)(x-y)=3y(x-y)²

3y（x^2-2xy+y^2）=3y（x-y）^2

3x^2y-6xy^2+3y^3=3x^2y-3xy^2+3y^3-3xy^=3xy(x-y)+3y^2(y-x)=(x-y)(3xy-3y^2)=3y(x-y)^2