Answer
$x=\{ -3,3 \}$
Work Step by Step
Using the properties of equality, the given equation, $
5x^2-45=0
,$ is equivalent to
\begin{align*}
5x^2-45&=0
\\
5x^2&=45
\\\\
\dfrac{5x^2}{5}&=\dfrac{45}{5}
\\\\
x^2&=9
.\end{align*}
Getting the square root of both sides (Square Root Property), the equation above is equivalent to
\begin{align*}
x&=\pm\sqrt{9}
\\
x&=\pm3
.\end{align*}
Hence, the solutions are $
x=\{ -3,3 \}
$.
