An e-reader manufacturer expects to sell 60,000 units each year if the selling price is $220. If the selling price is reduced to $170, then the manufacturer expects sell 140,000 units each year. a. Assume that the relationship between selling price ($) and units sold (1000s) is linear. Find the equation of the line that describes this relationship. Write your answer in slope-intercept form. Let x represent the selling price and y represent the units sold (1000s).
b. Use your equation from part (a) to estimate the number of units that the manufacturer expects to sell if the selling price is $150. Use the approximate values for slope and y-intercept found in part a.