数学公式（a-b）的三次方

Question

如题所述

Answer 1

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

Answer 2

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