#### Answer

$\color{blue}{\left\{-8, -3.8, 0, 4.5, 7.5\right\}}$

#### Work Step by Step

RECALL:
Zero-Factor Property:
If $ab = 0$, then either $a=0$ or $b=0$ or both are $0$.
Use the property above to obtain:
\begin{array}{cccccc}
-2m=0 &\text{or} &m+3.8=0 &\text{or} &m-7.5=0 &\text{or} &2m-9=0 &\text{or}& m+8=0
\end{array}
Solve each equation to obtain:
$-2m=0
\\\frac{-2m}{-2}=\frac{0}{-2}
\\m=0$
or
$m+3.8=0
\\m=0-3.8
\\m=-3.8$
or
$m-7.5=0
\\m=0+7.5
\\m=7.5$
or
$2m-9=0
\\2m=0+9
\\2m=9
\\\frac{2m}{2} =\frac{9}{2}
\\m=4.5$
or
$m+8=0
\\m=0-8
\\m=-8$
Thus, the solution set is $\color{blue}{\left\{-8, -3.8, 0, 4.5, 7.5\right\}}$.