In $s(m) = 1200 + 150m$, one number stands alone and one number is multiplied by $m$. Which of these would represent money that is added each time another membership is sold?

"For each membership" means "for 1 membership." In a line like $y = b + mx$, what part tells you how much $y$ increases when $x$ increases by 1?

Enter s(m) = 1200 + 150m into Desmos. Then create a table for this function and add two rows, one with $m=0$ and one with $m=1$. Look at the two $s(m)$ values and find how much the total increases when $m$ goes from 0 to 1; that increase is the number of dollars raised for each membership.

The function is

This matches the general linear form $y = b + mx$.

• The constant term $1200$ is the starting amount, before any memberships are sold.
• The coefficient $150$ is multiplied by $m$, the number of memberships, so it tells how much the total changes when $m$ increases.

The question asks: "How many dollars are raised for each membership sold?"

"For each membership" means for every increase of 1 in $m$, how much does $s(m)$ (the total dollars) increase? In a linear function, that is exactly the coefficient of the variable representing the number of items—in this case, the coefficient of $m$.

Looking at $s(m) = 1200 + 150m$:

• The constant term $1200$ is the amount raised before selling any memberships ($m = 0$).
• The coefficient of $m$ is $150$, so the total increases by $150 whenever 1 more membership is sold.

Therefore, the club raises 150 dollars for each membership sold, so the correct answer is 150.