Final answer:
The set of real numbers greater than or equal to -10 is expressed as [-10, ∞) in interval notation. The graph of a constant function like f(x) = 20, where 0 ≤ x ≤ 20, is a horizontal line between x=0 and x=20.
Step-by-step explanation:
The set of real numbers greater than or equal to -10 in interval notation is written as [-10, ∞). This means that the set includes -10 (as indicated by the square bracket) and extends indefinitely to the right on the number line towards positive infinity (as indicated by the parenthesis, since infinity is not a number that can be reached).
Additionally, when labeling a graph with a function such as f(x), you typically mark the x-axis with values of x and the y-axis with values of f(x). If the function f(x) is a constant value, such as f(x) = 20, the graph will be a horizontal line at the y-value of 20. When the domain is restricted as in 0 ≤ x ≤ 20, the horizontal line will only be drawn between these two x-values, inclusive of both 0 and 20, reflected by having closed dots on the graph at the points where x equals 0 and 20.