1. if demand is perfectly elastic the demand curve is horizontal
2. if demand for x shifts right as the price of good y increases, then x and y are substitutes
3. supply shifts rightward if input prices rise
4. it is possible for an economy to be inside its production possibilities frontier even if all workers who are willing and able to work have jobs.
5. if demand is elastic, if price decreases total revenue to the sellers increases.
6. if demand shifts right and supply left, then we know equilibrium quantity decreased but we do not know the change in equilibrium price.
7. Adam Smith's "invisible hand," analogy showed how selfish behavior can be harmful for an economy overall.
8. if demand shifts right and supply left, then we know equilibrium price increased, but we do not know the change in equilibrium quantity.