Precalculus (6th Edition) Blitzer

Step 1. Given $\frac{x^2}{9/4}+\frac{y^2}{25/4}=1$, we can identify $a^2=\frac{25}{4}, b^2=\frac{9}{4}$, thus $c=\sqrt {a^2-b^2}=2$. The ellipse is centered at $(0,0)$ with a vertical major axis. Step 2. We can graph the equation as shown in the figure, and the foci can be located at $(0, \pm2)$