for letters a,b,c,d,e,f
-how many arrangements can there be with 'a' and 'b' next to eachother?
(5! x 2)?
-how many arrangements can there be with 'a' and 'b' not next to eachother?
(6!) - (5! x 2)?
-how many arrangements can there be with 'a' and 'b' next to eachother, but with 'a' and 'c' not next to eachother?
thanks for the help.