D(p)=3000(10-p)         MC(x)=(x/6000)+4

a, What is the equilibrium(price & quantity) in this market?

b, Find those price & quantity that maximize the sume of consumers' surplus and producer's profit.

c, Assume that the world price is 5.
    What happens if the free importation of the good is allowed?
Calculate the price,
    the quantity consumed, and the quantity supplied by the domestic producer.

d, Find the level of subsidy, with which the domestic producer would produce and sell just as it did in part b.

e, There is one another monopolistic market, D'(p)=6000(8-p); MC'(x)=(x/6000)+4.
    What happens when these 2 monopolistic markets are INTEGRATED?

Thank you!