Can somebody help?

2. [20 points Give short answers to each of the following parts. Each answer should be at most a few sentences. Be sure to define any notation that you use (a) Let ? = {a, b), and we say a string w E ?. contains a double letter if aa or bb is a substring of w. Define the language A-( u, E ?. I to contains exactly one double letter). For example, baaba has exactly one double letter,but baaaba has two double letters. Give a regular expression for A. (b) Suppose that we are in the process of converting a CFG G with -0,1 into Chomsky normal form. We have already applied some steps in the process, and we currently have the following CFG: In the next step, we want to remove the e-rule A-+ ?. Give the CFG after carrying out just this one step