equivalent. 2.2.6. Over ? (a, b,c), are the regular expressions in each pair equivalent? (a) (a Ub) a" and ((a U b)a) (b) and e (c) ((a U b)c)* and (ac U bc) (d) b(ab Uac) and (ba U ba)(bUc) 2.2.7 Simplify: (c) (a*b)' U (b a)" (d) (a Ub)'ala Ub)* 2.2.8. Show that (aa)'a a(aa)'. 2.2.9. Simplify the following regular expressions. (a) (????)" (b) (? u aa)(eUaa)" (c) a(eu aa)"au ? (e) (a Ue)a b (f) (?? aa)"(eUaa)aua (h) (? Uaafe u aa)" (ab U b) U (ab U b) (i) (a Ub)(e Uaa)*(e Uaa) U (a Ub) (1) a b(a U b)a'b)'(a Ub)(aa)* Ua(aa) Ua b(a U b)a b)