[T] The manager at a skateboard shop pays his workers a monthly salary S of $750 plus a commission of $8.50 for each skateboard they sell.
a. Write a function y=S(x) that models a worker’s monthly salary based on the number of skateboards x he or she sells.
b. Find the monthly salary when a worker sells 25, 40, or 55 skateboards.
c. Use the INTERSECT feature on a graphing calculator to determine the number of skateboards that must be sold for a worker to earn a monthly income of $1400. (Hint: Find the intersection of the function and the line y=1400.)
