Charles 'n Marge sell custom-build cabinet units for motor homes. The function P(x) = - 1.25x2 + 900x - 5500 gives the profit when they build and sell a cabinet units. Find a) the profit when 100 units are sold dollars b) the average profit per unit as a function of x dollars per unit c) the rate that profit is changing when exactly 100 units are sold dollars per unit d) the number of units that must be sold in order to maximize profit. Round to the nearest whole number if necessary: units e) the maximum profit possible (using your whole number answer from part d) units