## Precalculus (10th Edition)

$x_{1}$=3 $x_{2}$=-3
$x^{2}$-9=0 Add 9 to both sides $x^{2}$-9+9=0+9 Simplify $x^{2}$=9 Take the square root of both sides $\sqrt x^{2}$=$\pm\sqrt 9$ $x_{1}$=3 $x_{2}$=-3