(a-b)(3ab+2a²b-b³)
问题描述:
(a-b)(3ab+2a²b-b³)
答
原式=a(3ab+2a²b-b³)-b(3ab+2a²b-b³)
=3a²b+2a³b-ab³-3ab²-2a²b²+b^4