Answer
$x=\pm9$
Work Step by Step
$\bf{\text{Solution Outline:}}$
To solve the given equation, $
x^2=81
,$ take the square root of both sides (Square Root Property). Then simplify the resulting radical.
$\bf{\text{Solution Details:}}$
Taking the square root of both sides (Square Root Property), the equation above is equivalent to
\begin{array}{l}\require{cancel}
x=\pm\sqrt{81}
.\end{array}
Simplifying the radical results to
\begin{array}{l}\require{cancel}
x=\pm\sqrt{(9)^2}
\\\\
x=\pm9
.\end{array}