The fundamental laws of economics are based on the use of the model of supply and demand and their potential balance. As we know from theory, such a balance is defined by the state in which the number of goods or services consumers want to purchase is fully equal to the number of goods and services that producers are willing to offer. Including, in the balance phase, an equilibrium price is outlined, which is what stimulates the harmony between supply and demand. However, this balance is dynamic: in other words, it is quite easy to break it. This is relevant in the case of a surplus of goods or services on the market, which can be eliminated by reducing the price of a commercial product. If the surplus is relevant to the market, the equilibrium price must fall (graphically, this means to move downward). Such a price decrease will lead to an increase in demand and, as a consequence, a decrease in producers’ supply.
In the case of A, there is an increase in supply and a decrease in demand. So there is a surplus here, so it is recommended to lower the equilibrium price in order to increase demand and thus reduce supply. In the case of B, supply decreases while demand increases: hence, there is a noticeable deficit. To get rid of it, the price must rise. This will attract new supply and somewhat reduce demand until equilibrium is reached again. In the case of C, both metrics are increasing, so the effect on the equilibrium price is uncertain. We need to investigate further the rate of change in demand and supply (separately) to see whether such an increase can lead to a deficit or surplus. The same conclusions are typical for case D, in which both metrics tend to decline.