Answer
$\left\{-2\sqrt{2}, 2\sqrt{2}\right\}$
Work Step by Step
Add $64$ to both sides:
$8x^2=64$
Divide $8$ on both sides to obtain:
$x^2=8$
Factor $8$ so that one factor is a perfect square:
$x=\pm \sqrt{4(2)}
\\x=\pm \sqrt{2^2(2)}
\\x=\pm 2\sqrt{2}$
Thus, the solution set of the given equation is $\left\{-2\sqrt{2}, 2\sqrt{2}\right\}$.
