Final answer:
The given equation 6y = 12x represents a direct variation, and the constant of variation is 2.
Step-by-step explanation:
The given equation 6y = 12x represents a direct variation. In direct variation, two values are directly proportional to each other, meaning that a change in one value results in a proportional change in the other. The constant of variation, denoted as k, represents the ratio between the two variables. For the given equation, we can rewrite it as y = 2x, which shows that the constant of variation is 2.