easiest thing to do is combine like terms. There are 9 2's, which means 9(2) which equals 18. Now for the X's. There are 9 X's meaning (9)x which is 9x. This all makes up
Since we know how much Olivia spent total, and we know how much she spent on the sunglasses, we just subtract 16.35 from 39.74, and the final answer is 23.40