Question

已知1/a-1/b=3,求2a+3ab-2b/a-2ab-b的值

Answer 1

1/a-1/b=3

(b-a)/(ab)=3

a-b=-3ab

(2a+3ab-2b)/(a-2ab-b)

=[2(a-b)+3ab]/[(a-b)-2ab]

=(-6ab+3ab)/(-3ab-2ab)

=(-6+3)/(-3-2)

=(-3)/(-5)

=3/5