22. a. I think this is profit? or is it something else entirely. 22.b. I think this is a decreasing function because it is a demand function but I'm not sure how to explain that. 23.a-c this one has a different curve and I honestly have no idea where to start now that we just started prices.

60 consumer surplus (CS) 40 p = D(x) =60 - 0.6x Price $p per book 20 20 40 60 80 100 Quantity r (text books) In general, economists define the consumer surplus (or utility) to be the area between the demand curve p = D(x) and the line p = p*, where p* is some fixed price. 22. (a) What does the area of the shaded rectangle in the above figure represent? (b) Explain why D(x) is generally a decreasing function of r. 23. Now let's consider a different demand curve, with p = D(x) = (x - 30)?. a) Graph that curve on the region 0