Final answer:
The domain of the function f(x) = 165x, representing the number of days a vacation home is rented for, is a) x ≥ 0.
Step-by-step explanation:
The domain of a function represents the set of all possible inputs (x values) for which the function is defined. In this case, the function f(x) = 165x represents the number of days a vacation home is rented for, so the domain should be restricted to non-negative values, as you can't have a negative number of rental days.
Therefore, the correct domain for this function is option a) x ≥ 0. This means that the function is defined for all non-negative real numbers.