Suppose quantity demanded is given by Qd=100-P, and quantity supplied is given by Qs=20+3P. In this case, find equilibrium price, P*, and equilibrium quantity, Q*. Draw the market supply and demand curves. If due to an external factor (give an example), the new supply equation turns out to be Qs=40+3P, what happens to equilibrium price and quantity?
Explain your work and draw graphs.