Work Step by Step
The symbol $\in$ means that the number is an element of the set. The symbol $\not \in$ means that the number is NOT an element of the set. Since $9$ is in the given set, then the missing symbol in the blank is $\in$
You can help us out by revising, improving and updating this answer.Update this answer
After 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.