Determine whether or not the following languages are regular. If the language is regular then give an NFA or regular expression for the language. Otherwise, use the pumping lemma for regular languages or closure properties to prove the language is not regular.

3. L = {a" : n=3k for some k >0} 2. L = {b^ak : n > 0, k >0} U {abk : k > 0, n >0}