Answers may vary. $y=-x^2$
Work Step by Step
The vertex must be at (0,0) and open downward. For the vertex to be at the origin, the axis of symmetry must be at $x=0$.
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.