Write a system of equations to describe the situation below, solve using elimination, and fill in the blanks. Ron is a shoe salesman, and he works on commission. This week, there is a special incentive to sell shoes and boots by a certain company. Yesterday, Ron sold 4 pairs of shoes and 4 pairs of boots, earning $84 in commission. Today, he sold 9 pairs of shoes and 4 pairs of boots, earning a total commission of $114. How much does Ron earn for the sale of each type of footwear?