Bill lent some money to his two brothers. He wrote down the amounts so he would not forget. The list shows his younger brother with −$12.75 and his older brother with $0. Which of the following statements best describes the amounts?

i think it might be a but you might want a second opinion

the revenue of the fitness center, y, is the product of two factors: the number of members and the fee paid by each member. there are 320 members now, but number of members goes down by 10 for each $5 increase in fees, so if x is the number of $5 price increases then members is equal to (320 - 10x). since the fee is currently $45, and the fee increases by $5 for every price bump x, the fee is given by (45 + 5x). so, revenue y is given by y = (320 - 10x)(45 + 5x).