Answer
$\frac{x^2}{27}+\frac{y^2}{36}=1$
Work Step by Step
Step 1. With the given conditions, we have $c=3, a=6$; thus $b^2=6^2-3^2=27$, with foci on the y-axis.
Step 2. The center is at $(0,0)$, so we can write the equation as $\frac{x^2}{27}+\frac{y^2}{36}=1$
