x^2-y^2-z^2=0
(x^2-y^2-z^2)(x+y+z)=0
x^3-y^3-z^3+x^2*y+x^2*z-y^2*x-y^2*z-z^2*x-z^2*y=0
x^3-y^3-z^3=-x^2*y-x^2*z+y^2*x+y^2*z+z^2*x+z^2*y
-x^2*y-x^2*z+y^2*x+y^2*z+z^2*x+z^2*y=(x-y)(x-z)A
可解
x^2-y^2-z^2=0
(x^2-y^2-z^2)(x+y+z)=0
x^3-y^3-z^3+x^2*y+x^2*z-y^2*x-y^2*z-z^2*x-z^2*y=0
x^3-y^3-z^3=-x^2*y-x^2*z+y^2*x+y^2*z+z^2*x+z^2*y
-x^2*y-x^2*z+y^2*x+y^2*z+z^2*x+z^2*y=(x-y)(x-z)A
可解