Explanation:
Charlie's monthly pay, P, can be represented as a linear function of the number of items sold, q. The monthly salary of $2,000 represents the y-intercept of the line, and the commission of $100 per item sold represents the slope of the line.
Thus, the model for Charlie's monthly pay, P(q), can be expressed as:
P(q) = 100q + 2000
where q is the number of items sold in a month, and P(q) is Charlie's monthly pay in dollars.