Is the answer i did right or wrong?

Yes, the answer you jotted down is actually incorrect!

It's wrong, the right answer is D.

Step-by-step explanation:

Good luck, and keep working hard ! :)

point a is the center of the circle that passes through points e, f, and g and the center of the circle that passes through points x, y, and z.

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).