已知1/a+1/b=3,求(a-2ab+b)/(3a+2ab+3b)的值

问题描述:

已知1/a+1/b=3,求(a-2ab+b)/(3a+2ab+3b)的值

1/a+1/b=3
(a+b)/ab=3
a+b=3ab
(a-2ab+b)/(3a+2ab+3b)
=(3ab-2ab)/(9ab+2ab)
=1/11