Final answer:
In the market for American-made cars, a decrease in the U.S. selling price of Japanese-made cars and a decrease in the price of steel used to make American-made cars would result in a fall in the equilibrium price and quantity of American-made cars.
Step-by-step explanation:
In the market for American-made cars, if there is a decrease in the U.S. selling price of Japanese-made cars (a substitute for American-made cars) and at the same time, the price of steel in the U.S., used to make American-made cars, decreases, the equilibrium price and quantity would be expected to fall.
This is because the decrease in the price of Japanese-made cars makes them more attractive to consumers, leading to a decrease in demand for American-made cars. Furthermore, the decrease in the price of steel lowers the production cost for American-made cars, allowing car manufacturers to reduce their selling price without sacrificing their profit margin.
As a result, both the equilibrium price and quantity of American-made cars would likely decrease, leading to a shift in the market for American-made cars.