x^6-y^6=(x^3+y^3)(x^3-y^3)
=(x+y)(x^2-xy+y^2)(x-y)(x^2+xy+y^2)
=(x+y)(x-y)[x-(根号3)yi][(x+(根号3)yi][3x-(根号3)yi][3x+-(根号3)yi]/4