please answer both questions

3. Book Section 1.3 Problem 10 (p. 60) Use your wits to solve each of the following language equations for the unknown language. a. {,a,ab}L={b,ab,ba,aba,abb.abba} b. L{a,b}={a,baa,b,bab} d. L{,a}={,a,b,ab,ba,aba} f. L{b,,ab}={abb,ab,abab,bab,b,bb} 4. Explain why {a,b,c} could be an alphabet but the following could not: a. {,a,b,c} b. abc c. {abc} d. (abc)