How does a 20-dollar subsidy effect the supply curve of Oil per barrel? Represent graphically and dentify the type of good, and explain how the changes will affect demand. Pepsi price declines what happens to the demand for Coca Cola? 6. A free market can be described by the equations Qd-178-3P and Qs--112 + 14P. Solve algebraically the equilibrium conditions in this market (Find equilibrium P and Q) and illustrate a decrease in supply. Explain how this free market is effected.