【计算,分解因式】x²(x-y)+y²(y-x)

问题描述:

【计算,分解因式】x²(x-y)+y²(y-x)

原式=(x^2-y^2)(x-y)
=(x+y)(x-y)^2若x²+y²-6y+4x+13=0,则x²-y ²=??x^2+y^2-6y+4x+13=0
(x+2)^2+(y-3)^2=0
x+2=y-3=0
x=-2 y=3
所以x^2-y^2=4-9=-5