4a²-3a-2（2a平方-4a=1）怎么算啊,

题目抄写不准确,现分情况解答,相信应该有楼主所需要的情况:
(1) 4a²-3a-2(2a²-4a-1)
=4a²-3a-(4a²-8a-2)
=4a²-3a-4a²+8a+2
=5a+2
(2) 4a²-3a-2(2a²-4a+1)
=4a²-3a-(4a²-8a+2)
=4a²-3a-4a²+8a-2
= 5a-2