Answer
$[-6,-3]$
Work Step by Step
We can remove the absolute sign to get: $-3\leq 2x+9\leq 3\longrightarrow -12\leq 2x\leq -6\longrightarrow -6\leq x\leq -3$ or in interval notation $[-6,-3]$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.