Graph $y=x^2-9$ on graph paper.  

1. Name the $y$-intercept. What is the connection between the $y$-intercept and the rule $y=x^2-9$?

   Answer (a):

   The $y$-intercept is where $x = 0$.
   $y=\left(0\right)^2-9$

2. Name the $x$-intercepts. What is the connection between the $x$-intercepts and the rule $y=x^2-9$?

   Answer (b):

   The $x$-intercepts are where $y = 0$.
   $0=x^2-9$