Question

b/1-a/2=2,,求3a-7ab-6b/-2b+3ab+a

能说说为什么吗？老师？

Answer 1

1/ b-2/a=2(等式两边同时乘以ab)
a-2b=2ab

(-2b+3ab+a)/(3a-7ab-6b)
=(a-2b+3ab)/(3a-6b-7ab)
=[(a-2b)+3ab]/[3(a-2b)-7ab]
=[2ab+3ab]/[3*2ab-7ab]
=5ab/(-ab)
=-5

Answer 2

b/1-a/2=2
ab/(a-2b)=2
a-2b=2ab

所以原式=[3(a-2b)-7ab]/[(a-2b)+3ab]
=[3(2ab)-7ab]/[(2ab)+3ab]
=-ab/5ab
=-5