Answer
$x \approx 17.33$
Work Step by Step
RECALL:
$\ln{e^m}=m$
Take the natural logarithm of both sides to obtain:
$\ln{e^{0.08x}}=\ln{4}$
Use the rule above to obtain:
$0.08x=\ln{4}$
Divide both sides by $0.08$ to obtain:
$x = \dfrac{\ln{4}}{0.08}$
Use a scientific calculator to obtain:
$x=17.32867951
\\x \approx 17.33$