Each student in Mr. Carey’s class donated 15$ to a charity there are 25 students in the class. Which expression could have been used to calculate the total amount donated?

9x

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).

to complete this square you have to rotate about the origin 270 degrees clockwise.