1, demand increases, supply decreases: the equilibrium quantity increases or decreases indefinitely, and the equilibrium price increases.

2. Demand decreases, supply increases: the equilibrium quantity increases or decreases indefinitely, and the equilibrium price decreases.

3. Demand increases, supply increases: the equilibrium quantity increases, and the equilibrium price increases or decreases indefinitely.

4. Demand decreases, supply decreases: the equilibrium quantity decreases, and the equilibrium price increases or decreases indefinitely.

Conclusion:

1. If demand and supply change in the opposite direction, the equilibrium price always changes with the direction of demand change, but the equilibrium quantity is uncertain.

2. If demand and supply change in the same direction, the equilibrium quantity changes in the same direction as supply and demand, and the equilibrium price increases or decreases according to the degree of supply and demand change.

Extension:

The relationship between market supply and demand and price, first of all, is that market value or production price determines price, which is the internal basis and entity of price formation and movement and the center of market price fluctuation. Price regulates the relationship between market supply and demand, and the relationship between market supply and demand reacts on price, which becomes the basic factor that dominates or affects the formation and movement of market price. Therefore, they influence and restrict each other.

For reference.