## Intermediate Algebra: Connecting Concepts through Application

$(-\infty, 3]$
The interval ends at, and includes, $3$. This means that a bracket will be used on the right part of the interval notation. The interval goes all the way to the left without bound, so the interval goes to negative infinity. This means that a parenthesis will be used on the left part of the interval. Therefore the interval notation of the given interval is $(-\infty, 3]$.