Which property is illustrated by the following ?
if a = b + 7 and b + 7 = 9, then a = 9​

Step-by-step explanation:

Associative property

We know

a + (b + c) = (a + b) + c

a = b + 7

b + 7 = 9

Rearrange Eq. 2

9 = b + 7

a = b + 7

Hence,

Value of a is 9

it is contrapositive

i could not see the question too well so check yourself again too . this is because i want you to get it correct.

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).