What are the elements of each order in D_n+Z_9 for n = 7 and 11?

[ccrfan44]

Pick a number n which is the product of 2 distinct primes 5 or more. Find the number of elements of each order in the groupd D(sub)n+Z(sub)9, completely explaining your work. Verify that these number add up to the order of the group.

Ive used 7 and 11 as my primes. So now do I use these primes in D_n since to where i get D_7+Z_9 and D_11+Z_9? This is where I am confused.

 

[ccrfan44]

Also once i have that info, then where do i go from here?