Answer
The solution set is $\left\{-7, 0, 7\right\}$.
Work Step by Step
Factor out $2x$ to find:
$2x(x^2-49)=0
\\2x(x^2-7^2)=0$
RECALL:
A difference of two squares can be factored using the formula:
$a^2-b^2=(a-b)(a+b)$
Factor the difference of two squares to find:
$2x(x-7)(x+7)=0$
Equate each factor to 0 then solve each equation to find:
$2x=0 \text{ or } x-7=0 \text{ or } x+7 = 0\\
x=0 \text{ or } x=7 \text{ or } x=-7$
The solution set is $\left\{-7, 0, 7\right\}$.
