(x+y)的二次-x的二次y的二次得多少
问题描述:
(x+y)的二次-x的二次y的二次得多少
答
(x+y)^2-x^2y^2
=(x+y+xy)(x+y-xy)
(x+y)的二次-x的二次y的二次得多少
(x+y)^2-x^2y^2
=(x+y+xy)(x+y-xy)