Answer
$x=-4$
Work Step by Step
To solve the given equation, make the two sides have the same base.
Note that $\frac{1}{5} = 5^{-1}$ so the given equation is equivalent to:
$5^{x+3} = 5^{-1}$
Use the rule $a^m=a^n \longrightarrow m=n$ to obtain:
$x+3 = -1$
Subtract 3 to both sides of the equation to obtain:
$x=-1-3
\\x=-4$
