## Precalculus (6th Edition) Blitzer

$circle$; $parabola$; $ellipse$; $hyperbola$.
From the given general equation, when $A=C$, the equation will be a $circle$; when $AC=0$, it will be a $parabola$; when $AC\gt0, A\ne C$, it will be an $ellipse$; and when $AC\lt0$, it will be a $hyperbola$.