For the demand equation, express the total revenue R as a function of the price p per item. R(p) = 9 = -4p+ 80 Sketch the graph of the resulting function. 420 400 380 360 340 320 300 280 280 240 220 200 480 160 140 No Solution 120 100 80 60 Fill Graph Layers After you add an object to the graph you can use Graph Layers to view and edit its properties.