a²+2ab-3b²=0
(a-3b)(a+b)=0
a=3b或a=-b
当a=3b时
a/b-b/a-a²+b²/ab
=(3b/b)-b/(3b)-(9b²+b²)/(3b²)
=3-1/3-10/3
=-2/3
当a=-b时
a/b-b/a-a²+b²/ab
=-1+1-(2b²/-b²)
=2
a²+2ab-3b²=0
(a-3b)(a+b)=0
a=3b或a=-b
当a=3b时
a/b-b/a-a²+b²/ab
=(3b/b)-b/(3b)-(9b²+b²)/(3b²)
=3-1/3-10/3
=-2/3
当a=-b时
a/b-b/a-a²+b²/ab
=-1+1-(2b²/-b²)
=2