Q3- Write a regular expression for each of the followings.

a) All words on = {, }, which has a different first and last letter.

Example: abbab, bbaaaba

b) All words on = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, which the decimal number is divisible by 4. A decimal number is divisible by 4 if the last two digits are divisible by 4.

Example: 889132, 888976184

c) Try part b again but this time, do not allow leading 0s.