若3am-n÷4a=3/4,且2m+n=2,求3m-4n.

问题描述:

若3am-n÷4a=

3
4
,且2m+n=2,求3m-4n.

∵3am-n÷4a=

3
4

∴m-n=1,
∵2m+n=2,
m−n=1
2m+n=2

解得:
m=1
n=0

故3m-4n=3×1-0=3.