IF you are solving for N, then I think this is the way to do it.
6=1-2n+5
combine light terms:
6=(1+5)-2n
6=-2n+6
now try to get N by itself so you subtract 6 on both side:
6=-2n+6
-6 -6
now you have 0=-2n or -2n=0
now divide both sides by -2
-2n/-2 = 0/-2
so it's a no solution. but if it doesn't give you that option, then n=0