Answer
Positive
Work Step by Step
Since the square root and the fact that the number is squared cancel, we are left with the original number. Thus, we see that $a$ must be positive.
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.