化简:2(3a-1)-3(2-5a 3a2)
问题描述：
化简:2(3a-1)-3(2-5a 3a2)
我这样做对不对：
2(3a-1)-3(2-5a+3a2)
=6a-2-6-15a-9a2
=6a-15a-8-9a2
=-9a-8-9a2
答
不对.
应该是
2(3a-1)-3(2-5a+3a2)
=6a-2-6+15a-18a
=6a+15a-18a-2-6
=3a-6