## Precalculus (6th Edition)

$\color{blue}{(-\infty, -6)}$
The given inequality is "$x$ is less than $-6$." The numbers included in this set are the numbers that are less than $-6$, which are to the left of $-6$ on the number line. The equivalent interval notation of the given inequality will have: $\bf\text{lower limit:}$ none, so negative infinity will be used. $\bf\text{upper limit:}$ $-6$, but a parenthesis will be used since $-6$ is not included Therefore, the interval is: $\color{blue}{(-\infty, -6)}$