Final answer:
To find the time until the evening performance given the time until the matinee, use the equation y = x - 2, where x is the time until the matinee and y is the time until the evening performance.
Step-by-step explanation:
The question is about writing an equation to determine the time until the evening performance at a theater based on the time until the matinee performance. We are given that the evening performance begins 2 hours after the matinee. Therefore, the equation that represents the relationship between the number of hours x until the matinee begins and the number of hours y until the evening performance begins would be:
y = x - 2
This equation assumes that as the time until the matinee decreases, the time until the evening performance also decreases by the same amount, minus 2 hours.