Question

已知1/a-1/b=3,求(2a-3ab-2b)/(a-2ab-b)的值是多少？

请快点回答

Answer 1

1/a-1/b=3
b/ab-a/ab=3
b-a=3ab
(2a-3ab-2b)/(a-2ab-b)=-(2b-2a+3ab)/-(b-a+2ab)=[2(b-a)+3ab]/b-a+2ab=(6ab+3ab)/(3ab+2ab)=9ab/5ab
因为1/a+1/b=3
所以a,b不等于0
所以9ab/5ab=1.8

Answer 2

∵1/a-a/b=3

∴(b-a)/ab=3

∴b-a=3ab

∴(2a+3ab-2b)/(a-2ab-b)

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

=[-6ab+3ab]/[-3ab-2ab]

=(-3ab)/(-5ab)

=3/5

Answer 3

1/a-1/b=3,

(b-a)/ab=3

a-b=-3ab

(2a-3ab-2b)/(a-2ab-b)
=(-2*3ab-3ab)/(-3ab-2ab)
=-9ab/-5ab
=9/5