D(x) is the price, in dollars per unit, that consumers are willing to pay for x units of an item, and S(x) is the price, in dollars per unit, that producers are willing to accept for x units. Find (a) the equilibrium point, (b) the consumer surplus at the equilibrium point, and (c) the producer surplus at the equilibrium point. D(x) = (x- 9)2, S(x) =x2 +2x+21 . . . (a) What are the coordinates of the equilibrium point? (Type an ordered pair.)