(a+b)^3=a^3+3a^2b+3ab^2+b^3 (a-b)^3=?

问题描述:

(a+b)^3=a^3+3a^2b+3ab^2+b^3 (a-b)^3=?
(a+b)^3=a^3+3a^2b+3ab^2+b^3 ,那么(a-b)^3=?

(a-b)^3=(a+(-b))^3=a^3+3a^2(-b)+3a(-b)^2+(-b)^3
=a^3-3a^2b+3ab^2-b^3