Identify the center, intercepts, and domain, and range of the equation
x^2/4+y^2/9=1
you need to review your ellipses. See whether you can derive these properties:
http://www.wolframalpha.com/input/?i=ellipse+x%5E2%2F4%2By%5E2%2F9%3D1
Your other ones should also be evident.