Answer
$x^2+y^2=9$
Work Step by Step
So using the fact that $\sqrt {x^2+y^2}$ = r, we have$\sqrt {x^2+y^2}$ = -3. Squaring both sides we get $x^2+y^2=9$.
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.