Final answer:
The relationship between the number of oil changes and the cost of car repairs is most likely inverse proportionality, represented by y = k/x, where increasing oil changes reduces repair costs. For a definitive answer, the specific equation or more context is needed.
Step-by-step explanation:
The relationship between the number of oil changes per year and the cost of car repairs can be described using the concept of proportion. If we assume that more frequent oil changes can lead to fewer car repairs, this suggests a form of inverse proportionality, where an increase in the number of oil changes (x) would lead to a decrease in the cost of car repairs (y). This could be represented by an equation of the form y = k/x, where k is a constant that represents the proportionality. However, to give a definitive answer, a specific equation or additional information would be essential.
Typically, direct proportionality is represented by a linear equation of the form y = kx, where an increase in x leads to a corresponding increase in y. Conversely, inverse proportionality is illustrated with an equation like y = k/x, where an increase in x results in a decrease in y. Neither exponential growth nor a quadratic relationship appears to fit the described scenario unless specific data suggests otherwise.