9a²-4b²=0
(3a+2b)(3a-2b)=0
3a+2b=0,b/a=-3/2
或3a-2b=0,b/a=3/2
a/b-b/a-(a^2+b^2)/(ab)
=(a^2-b^2)/(ab)-(a^2+b^2)/(ab)
=(2b^2)/(ab)
=2b/a
=±3
9a²-4b²=0
(3a+2b)(3a-2b)=0
3a+2b=0,b/a=-3/2
或3a-2b=0,b/a=3/2
a/b-b/a-(a^2+b^2)/(ab)
=(a^2-b^2)/(ab)-(a^2+b^2)/(ab)
=(2b^2)/(ab)
=2b/a
=±3