The range of a function is the set of all possible output values. Which statement describes the range?

• A. The set of input values.
• B. The set of possible output values.
• C. The set of x-values where the function is undefined.
• D. The set of y-values that do not occur.

Answer: (B)

The range is about the outputs a function can produce. It’s the set of all possible y-values you can get when you plug in every allowed input. So the statement that matches is that the range is the set of possible output values.

Think of the domain as all the inputs you can use, and the range as all the results those inputs can give you. The other descriptions describe the inputs or the non-occurring outputs, not the outputs that actually occur. For example, with f(x) = sqrt(x), the domain is x ≥ 0, while the range is y ≥ 0—the outputs you can obtain are all nonnegative numbers.