5x-3x=2m-6m+1
2x=-4m+1
x=(-4m+1)/2
-3<(-4m+1)/2
-4m+1>-6
4m<7
m<7/4
(-4m+1)/2≤2
-4m+1≤4
4m≥-3
m≥-3/4
所以-3/4≤m<7/4