3a²+ab-2b²=0
(3a-2b)(a+b)=0
3a=2b或者a=-b
所以b/a=3/2或者b/a=-1
a/b-b/a-(a²+b²)/ab
=a/b-b/a-(a/b+b/a)
=a/b-b/a-a/b-b/a
=-2b/a
=2或者-3