Work Step by Step
If the parabola has its vertex at $(0,0)$ and its focus at $(p,0)$ then the equation is: $y^2=4px$. Hence here $p=-9$, thus the equation is: $y^2=-36x$
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.