text: ## Algebra 2 (1st Edition)
  
  A hyperbola with foci $( \pm 9,0)$ and vertices on the x-axis: Since the vertices are at $(\pm 4,0) \rightarrow a=4$. The foci are at $(\pm 9,0) \rightarrow ae=9$. Rewrite the equation in standard form: $\frac{x^2}{4^2}-\frac{y^2}{9^2-4^2}=1\\\frac{x^2}{16}-\frac{y^2}{65}=1$