已知:a+2b=0,则3a-b/a-4b
问题描述:
已知:a+2b=0,则3a-b/a-4b
答
已知:a+2b=0,则a=-2b
(3a-b)/(a-4b)
=(-6b-b)/(-2b-4b)
=-7b/(-6b)
=7/6