Answer
$(-3,3]$
Work Step by Step
The function remains constant in an interval when, moving from left to right, the y-values continue to remain constant for all x-values in that interval. For the graph in the question, the y-values remain constant for all values of $x$ between $-3$ and $3$. Since $-3$ is not included in the interval as it is represented by an open circle, it will be supported by a parenthesis. On the other hand, $3$ is included in the interval as it is represented by a closed circle. This means it will be supported by a square bracket.
Therefore, the function remains constant in the interval $(-3,3]$.
