(a) Write a regular expression for the language L on the alphabet { a, b, c } that recognises all strings in which the letter b either is the end of the string or is directly followed by the letter a . (That is, the same language as in Question 3).

(b) Write a regular expression for the language L , which is defined as being the complementary language to L ; that is, L is the set of strings over the alphabet { a, b, c } that are not in L .