## Algebra and Trigonometry 10th Edition

Standard form of a circle with center at the origin: $x^2+y^2=r^2$, in which $r$ is the radius. Standard form of a hyperbola with center at the origin and horizontal transverse axis: $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1~~$ It can be written as: $x^2-\frac{a^2}{b^2}y^2=a^2$ This last form is the form of the given equation, in which $a=b=12$.