5 times the product of x and y. The product of x and y means to multiply. That is where we get this: xy. 5 times that product is where we add 5 to it and get this: 5xy.
7 - 4x
We get this because we know he gets $4 an hour. We just do not know how many hours he babysat. The hours is X and we multiply that by 4.
8 - 5.5
Take 8.3 and subtract 2.8 to find x. Once we do that we get 5.5, and that is X.