(2a+b-3c)(2a-b+3c)答案是?
问题描述:
(2a+b-3c)(2a-b+3c)答案是?
以初中口吻回答
答
(2a+b-3c)(2a-b+3c)
=[2a+(b-3c)][2a-(b-3c)]
=4a^2-(b-3c)^2
=4a^2-b^2-9c^2+6bc