A shopkeeper buys a certain number of books for $720.If the cost per book was $5 less, the number of books that could be bought for $720 would be 2 more. Taking the original cost of each book to be $x, write an equation in x and solve it.​

a

step-by-step explanation:

strong negative correlation

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).