Question 23155
You have to remember a^2 =aa, a^3= aaa, etc.
So you should see that you have c and c^3.
Multiplying those you get c^4
You also have d^2 and d^2 again.
That gives you d^4 
So you end up with this as an answer:  c^4d^4

Hope this helps.
Cheers,
Stan H.