(x的6次方-y的6次方)除以(x的立方-y的立方)除以(x+y)

问题描述:

(x的6次方-y的6次方)除以(x的立方-y的立方)除以(x+y)
如题 拆开它~

(x^6-y^6)/(x^3-y^3)/(x+y)
=(x^3+x^3)(x^3-x^3)/(x^3-x^3)/(x+y)
=(x^3+x^3)/(x+y)
=(x+y)(x^2-xy+y^2)/(x+y)
=x^2-xy+y^2