## Precalculus (6th Edition)

domain: $(-\infty, +\infty)$ range: $\left\{-4\right\}$ Refer to the graph below.
RECALL: A function whose equation is of the form $f(x) = a$: (1) is a constant function, the graph of which is a horizontal line; (2) all points on the line have a y-coordinate of $a$; and (3) has the set of real numbers as its domain and $a$ as its range. Thus, the graph of the function $f(x)= -4$ is a horizontal line. All the points on the line have a y-coordinate of $-4$. Plot the points $(0, -4)$ and $(1, -4)$. (Refer to the graph in the answer part above.) The domain is $(-\infty, +\infty)$ while the range is $\left\{-4\right\}$.