Final answer:
The equation y - 0.072x + 318 can be used to find y, the number of sales, given x, the number of people who see a commercial for a specific product. The equation is not proportional because the graph has a positive slope.
Step-by-step explanation:
The equation y - 0.072x + 318 can be used to find y, the number of sales, given x, the number of people who see a commercial for a specific product. The b term in the equation, 318, represents the y-intercept, which tells us where the line intercepts the y-axis. The slope of the line, -0.072, represents how much y changes for each unit increase in x. Since the slope is negative, the equation shows a negative relationship between x and y. Therefore, the correct answer is option d) The equation is not proportional because the graph has a positive slope.