Prove the following: a) ex= y + y = x and b) + x = y + y = 2 + x = z

Description: write function lastfirst() that takes one argument—a list of strings of the format "lastname, firstname" —and returns a list consisting of two lists: (a) a list of all the last names (b) a list of all the first names

Mastercard managers are motivated to increase (1) the number of individuals who have and use a mastercard credit card, (2) the number of banks and other clents who issue mastercards to customers and/or employees, and (3) the number of locations that accept mastercard payments. discuss how mastercard could use its data warehouse to it expand each of these customer bases.

The first few lines of a script that say "using" that point the code to the right groups are called