Explain how to find reasonable domain values for a function

A reasonable domain and range is the set of values that exist for the function. The sets that are not reasonable are not considered domain and range. For instance, f (x) = 15√ (x - 3)

The reasonable domain is R, x ≥ 3 since you can't have negative value inside the radicand.

The reasonable range is R, f (x) ≥ 0 since the minimum value is 0 [Noting that x = 3 gives f (3) = 15√ (3 - 3) = 15√0 = 0]