Answer
$x=\dfrac{14\log0.1}{\log3}\approx-29.342646$
Work Step by Step
$3^{x/14}=0.1$
Apply $\log$ to both sides of the equation:
$\log3^{x/14}=\log0.1$
The exponent $x/14$ can be taken down to multiply in front of its respective $\log$:
$\dfrac{x}{14}\log3=\log0.1$
Solve for $x$:
$x=\dfrac{14\log0.1}{\log3}\approx-29.342646$
