Answer
See graph and explanations.
Work Step by Step
Step 1. Graph the equation as shown in the figure.
Step 2. Rewrite the equation as $\frac{y^2}{16}-\frac{x^2}{4}=1$; we have $a=4, b=2$ and thus $c=\sqrt {4^2+2^2}=2\sqrt {5}$
Step 3. As the center of the ellipse is at $(0,0)$ and the major axis is vertical, the foci are $(0,\pm2\sqrt {5})$ and the asymptotes are $y=\pm \frac{4}{2}x=2x$ as shown in the figure.
