x³+y³+z³=(x+y)(x²-xy+y²)+z³=(-z)[(x+y)²-3xy]+z³=z[z²-(-z)²+3xy]=3xyz故选D
选D x^3+y^3+z^3=x^3+y^3-(x+y)³拆分后得-3xy（x+y）x+y=-z可得3xyz
Dx^3+y^3+z^3-3xyz=(x+y+z)(x^2+y^2+z^2-xy-yz-xz)
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