Answer
$\color{blue}{\left\{-5, 5\right\}}$
Work Step by Step
Factor out $-3$ to obtain:
$-3(m^2-25)=0$
Since $25=5^2$, the given equation can be written as:
$-3(m^2-5^2)=0$
RECALL:
$a^2-b^2=(a-b)(a+b)$
Factor the binomial using the formula above to obtain:
$-3(m-5)(m+5)=0$
Use the Zero-Factor Property by equating each factor to zero to obtain:
$-3=0$ or $m-5=0$ or $m+5=0$
Solve each equation to obtain:
$-3=0$, no solution
or
$m-5=0
\\m=0+5
\\m=5$
or
$m+5=0
\\m=0-5
\\m=-5$
Therefore, the solution set is $\color{blue}{\left\{-5, 5\right\}}$.
