Answer
$\color{blue}{\left\{-4, 4\right\}}$
Work Step by Step
Factor out $5$ to obtain:
$5(x^2-16)=0$
Since $16=4^2$, the given equation can be written as:
$5(x^2-4^2)=0$
RECALL:
$a^2-b^2=(a-b)(a+b)$
Factor the binomial using the formula above to obtain:
$5(x-4)(x+4)=0$
Use the Zero-Factor Property by equating each factor to zero to obtain:
$5=0$ or $x-4=0$ or $x+4=0$
Solve each equation to obtain:
$5=0$, no solution
or
$x-4=0
\\x=0+4
\\x=4$
or
$x+4=0
\\x=0-4
\\x=-4$
Therefore, the solution set is $\color{blue}{\left\{-4, 4\right\}}$.
