Answer
$x \approx 3.17$
Work Step by Step
Add $4.7^x$ on both sides of the equation to obtain:
$135=4.7^x$
RECALL:
$\log_b{a^x} = x \cdot \log_b{a}$
Take the natural logarithm of both sides to obtain:
$\ln{135}=\ln{(4.7^x)}$
Use the rule above to obtain:
$\ln{135}=x \cdot \ln{(4.7)}$
Divide both sides by $\ln{(4.7)}$ to obtain:
$\dfrac{\ln{135}}{\ln{4.7}}=x$
Use a scientific calculator to obtain:
$3.169677962= x
\\x \approx 3.17$