x＾2(y+z)+y＾2（z+x）+z＾2(x+y）-(x＾3+y＾3+z＾3）-2xyz
问题描述：
x＾2(y+z)+y＾2（z+x）+z＾2(x+y）-(x＾3+y＾3+z＾3）-2xyz
答
x^2(y+z)+y^2(z+x)+z^2(x+y)-(x^3+y^3+z^3)-2xyz =x^2(y+z)+y^2*z+y^2*x+z^2*x+z^2*y-x^3-y^3-z^3-2xyz =x^2(y+z-x)+x(y^2+z^2-2yz)+(y^2*z+z^2*y-y^3-z^3) =x^2(y+z-x)+x(y-z)^2+[y^2(z-y)-z^2(z-y)] =x^2(y+z-x)+x...