已知b/a=3,求a^2+2ab-b^2/ab-a^2的值

问题描述:

已知b/a=3,求a^2+2ab-b^2/ab-a^2的值

b/a =3
b=3a
(a^2+2ab-b^2)/(ab-a^2)
=(a^2+6a^2-9a^2)/(3a^2-a^2)
=-1