Answer
See graph and explanations.
Work Step by Step
Step 1. Rewrite the equation as $\frac{x^2}{25}+\frac{y^2}{4}=1$; we can identify $a^2=25, b^2=4$. Thus $c=\sqrt {a^2-b^2}=\sqrt {21}$. The ellipse is centered at $(0,0)$ with a horizontal major axis.
Step 2. We can graph the equation as shown in the figure, and the foci can be located at $(\pm\sqrt {21},0)$
