(3) Prove that the following languages are nonregular via the Myhill-Nerode Theorem. All use the alphabet a, b. (The in (a) means numerical multiplication.) (b) Lb-(xby : # (x)-#b(y)]. (c) Le la ba b:i-j-k, i,j,k21. Here again #c(x) means the number of occurrences of the character c in the string x. (3x 12 = 36 pts