【不难的数学题】已知(a+b)除以2ab=3,则(3a-7ab+3b)除以(a+3ab+b)等于?RT

问题描述:

【不难的数学题】已知(a+b)除以2ab=3,则(3a-7ab+3b)除以(a+3ab+b)等于?
RT

a+b=6ab
=[3(a+b)-7ab]/[(as+b)+3ab]
=[3(6ab)-7ab]/[(6ab)+3ab]
=11ab/9ab
=11/9

(a+b)/2ab=3 (a+b)=6ab
(3a-7ab+3b)/(a+3ab+b)=(3(a+b)-7ab)/((a+b)+3ab)=(3*6ab-7ab)/(6ab+3ab)=11/9

因为 (a+b}/2ab=3 ,所以 同乘2ab得:a+b=6ab
(3a-7ab+3b )/ (a+3ab+b)
= 【3 (a+b )--7ab 】/ 【(a+b) +3ab 】 将a+b替换为6ab得
= [18ab - 7ab]/ [ 6ab + 3ab]
= 11ab/9ab
= 11/9
这道题不难,希望对你有帮助!

已知(a+b)除以2ab=3得a+b=6ab (3a-7ab+3b)/(a+3ab+b)=(18-7)ab/(6+3)ab=11/9

即a+b=6ab
原式=[3(a+b)-7ab]/[(as+b)+3ab]
=[3(6ab)-7ab]/[(6ab)+3ab]
=11ab/9ab
=11/9