4x+2m-1=3x
x+2m-1=0
x=1-2m
3x+2m=6x-1
-3x=-1-2m
x=(1+2m)/3
1-2m-(1+2m)/3=4
两边乘以3,得
3-6m-1-2m=12
-8m+2=12
-8m=10
m=-5/4