若a+b-ab=0,则(3a+3b-ab)/(2a+2b+ab)=
问题描述:
若a+b-ab=0,则(3a+3b-ab)/(2a+2b+ab)=
答
若a+b-ab=0, 则 a+b=ab
则(3a+3b-ab)/(2a+2b+ab)
=[3(a+b)-ab]/[2(a+b)+ab]
=(3ab-ab)/(2ab+ab)
=2ab/3ab
=2/3
答
a+b-ab=0
a+b=ab
(3a+3b-ab)/(2a+2b+ab)
=(3ab-ab)/(2ab+ab)
=2/3