What does the range of a function describe?

• A. The set of y-values
• B. The set of x-values
• C. The input values
• D. The slope of the graph

Answer: (A)

The range of a function is the set of all output values, the y-values, that the function can produce as you vary the input x over its allowed inputs. In other words, it lists every possible y that can come from the function. This is why the range is described as the collection of y-values the function can output.

For example, if a function outputs y = 2, 4, or 7 for its inputs, those numbers make up the range. The set of x-values corresponds to the domain (the inputs), and the slope describes how the output changes as the input changes, which is a different idea altogether.