6. Suppose the price for a certain product is D(x) = 40 - x - 3x when the demand for the product is x units, and the price function is S(x) = x + 3x when the supply is x units. a. (4 points) Find equilibrium price and quantity algebraically. 2 -40 P b. (2 points) Set up (but do not solve) the equation for consumer surplus. c. (2 points) Set up (but do not solve) the equation for producer surplus. 30 1/2+3x 30 10- 40-x2 3 butt 20