Chapter 9 - Solving Quadratic Equations - 9.3 - Solving Quadratic Equations Using Square Roots - Exercises - Page 501: 9

$x=4$ and $x=-4$

The given equation is $\Rightarrow x^2-16=0$ Add $16$ to each side. $\Rightarrow x^2-16+16=0+16$ Simplify. $\Rightarrow x^2=16$ Take the square root of each side. $\Rightarrow x=\pm\sqrt {16}$ Simplify. $\Rightarrow x=\pm4$ Hence, the solutions are $x=4$ and $x=-4$.