Final answer:
Mathematics - Analyzing factors in an equation one at a time using mathematical models.
Step-by-step explanation:
Mathematics
When considering the factors on the left-hand side of an equation, one at a time, while holding the other factors constant, we are using a mathematical model. This approach allows us to analyze the impact of each individual factor on the outcome of the equation. For example, in the context of a demand equation, we can determine how changes in price affect the quantity demanded by keeping other variables constant. By solving the system of equations that represent the model, economists can answer specific questions about the relationship between different variables.