The slope of a line is 3 and passes through the points (2,k) and (4,1) find the value of k.

slope=(1-k)/(4-2)

3=(1-k)/2

3×2=1-k

6-1=-k

k=-5

i think it is 18

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).