Which of the sets of ordered pairs represents a function?

a = {(−4, 5), (1, −1), (2, −2), (2, 3)}

b = {(2, 2), (3, −2), (9, 3), (9, −3)}

1. only a
2. only b
3. both a and b
4. neither a nor b

multiply length by height. multiply the length by the height, and then double the product. work out 10 x 10 results = 100 square inches, then work out 100 x 2 = 200. the answer is 200 square inches.

step-by-step explanation:

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).