Final answer:
The range of the function described as a horizontal line for 0 ≤ x ≤ 20 is the y-value the line represents, which is a constant. The exact value of the range isn't given, but it would be a single number since all x-values map to one y-value on a horizontal line.
Step-by-step explanation:
The range of a function refers to the set of all possible output values it can produce. Given that the graph of the function f(x) is a horizontal line, which typically indicates that for all inputs x, the output f(x) is constant. Since no specific equation is provided for this horizontal line, but we are to consider it for 0 ≤ x ≤ 20, we can deduce that this horizontal line is at a specific y-value within this x-interval.
If the graph of this function is indeed a horizontal line, then the range is simply the y-value to which this line corresponds. Without further information, we cannot state the exact value of the range, but it will be a single number, symbolizing that every x-value within the given domain will map to this y-value. If the hypothetical horizontal line lies at y = 1, for example, then the range of f(x) is {1}.