计算题(x+y)^2(y+z-x)(z+x-y)+(x-y)^2(x+y+z)(x+y-z).
问题描述：
计算题(x+y)^2(y+z-x)(z+x-y)+(x-y)^2(x+y+z)(x+y-z).
答
原式=(x+y)²[z²-(x-y)²]+(x-y)²[(x+y)²-z²]=(x+y)²z²-(x+y)²(x-y)²+(x+y)²(x-y)²-z²(x-y)²=z²[(x+y)²-(x-y)²]=4xyz²