Answer:
(-∞, ∞).
Explanation:
The range of a function refers to the set of all possible values that the function can output. In the case of the function f(x) = 3x + 9, the range can be determined by considering the domain of the function (which is typically all real numbers unless otherwise specified) and the behavior of the function.Since the function f(x) = 3x + 9 represents a linear equation, the range will extend infinitely in both positive and negative directions. This means that the range is all real numbers.In interval notation, the range of f(x) = 3x + 9 can be expressed as (-∞, +∞).