The demand for coffee is given by the following equation, where QD stands for the quantity demanded and P stands for price. QD= 100− 4P The supply of coffee is given by the following equation, where QS stands for the quantity supplied and P stands for price. QS= 10+ 2P a. What is the slope of demand? Slope = b. At what price is quantity demanded equal to zero (this is, graphically, the vertical intercept of Demand)? P = c. What is the slope of supply? Slope = d. At what price is quantity supplied equal to zero (this is, graphically, the vertical intercept of Supply)? P =