(3a+1)(2a-3)-6(a+2)(a-1)

问题描述:

(3a+1)(2a-3)-6(a+2)(a-1)

=(6a²-9a+2a-3)-6(a²-a+2a-2)
=6a²-7a-3-6a²-6a+12
=-13a+9