Answer
There are two $x$-intercepts: $-3$ and $3$.
The y-intercept is $-9$.
See the graph below.
Work Step by Step
In order to find the $x$-intercept, we have to plug $y=0$ into the equation, and the $x$-coordinate will give us the intercept itself.
$y=x^2-9$
$0=x^2-9$
$x^2=9$
$x=\pm3$
The same thing should be done for the $y$-intercept, however, here $x=0$ should be plugged into the equation.
$y=x^2-9$
$y=0^2-9$
$y=-9$
There are two x-intercepts: $-3$ and $3$
The y-intercept is $-9$
Few other points that will help us plot the graph:
If $x=1$
$y=1^2-9=-8$
The point $(1,-8)$ is on the graph.
If $x=-1$
$y=(-1)^2-9=-8$
The point $(-1,-8)$ is on the graph.
If $x=4$
$y=4^2-9=7$
The point $(4,7)$ is on the graph.
