Answer
$\frac{x^2}{9}+\frac{y^2}{4}=1$.
Work Step by Step
Start from the standard equation $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$. Based on the given conditions, we have $2a=6, a=3$ and $2b=4, b=4$. Thus the equation is $\frac{x^2}{9}+\frac{y^2}{4}=1$.
