What mathematical expression represents a direct variation relationship?

In a direct variation relationship, the variables involved maintain a proportional relationship such that if one variable increases, the other variable also increases in a consistent manner. This relationship can be expressed mathematically in the form of an equation.

The expression that correctly represents a direct variation is y = kx, where y is directly proportional to x, and k is the constant of proportionality. This means that for every unit increase in x, y will increase by k units, demonstrating a direct correlation.

In this case, your answer aligns with the core principles of direct variation, where increasing one variable results in a proportional change in the other, thus confirming the direct relationship defined by the constant k. Therefore, y = kx effectively captures the essence of direct variation.