Answer to Question 1
The profit-maximizing output is 3 units, because that is the quantity for which the marginal revenue equals the marginal cost. The price is 18 a unit.
Answer to Question 2
The price of eggs will fall. As it falls, the quantity of eggs supplied will fall and the quantity of eggs demanded will rise. Eventually, at the new market equilibrium price, quantity demanded will be equal to quantity supplied. The market will be in equilibrium.