Answer
$[-3,3]$
Work Step by Step
We are given the function:
$f(x)=9-x^2$
Graph the function.
The solution of the inequality $f(x)\geq 0$ consists of the values of $x$ for which the graph of the function is above the $x$-axis.
Determine the zeroes of the function:
$9-x^2=0\Rightarrow x^2=9\Rightarrow x=\pm 3$
The solution of the inequality is:
$[-3,3]$
