#### Answer

$n=-5$

#### Work Step by Step

Using the properties of equality, the value of the variable that satisfies the given equation, $
3n-5=8n+20
,$ is
\begin{array}{l}\require{cancel}
3n-8n=20+5
\\\\
-5n=25
\\\\
n=\dfrac{25}{-5}
\\\\
n=-5
.\end{array}