(a-b)[(a+b)3-2ab(a2-b2)]

问题描述:

(a-b)[(a+b)3-2ab(a2-b2)]

(a-b)[(a+b)3-2ab(a2-b2)]
=(a²-b²)[(a+b)²-2ab]
=(a²-b²)(a²+b²)
=a^4-b^4不是有个中括号吗?