Answer
$x^2+y^2+8y=0$
Work Step by Step
Center=$(0,-4)$ Radius=$4$
Equation:
$(x-0)^2+(y+4)^2=4^2$
$\implies x^2+y^2+8y+16=16$
$\implies x^2+y^2+8y=0$
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.