Answer
$2^{7/3}\approx5.040$
Work Step by Step
Step 1. Rewrite the equation as $log_{7}(x)=\frac{2}{3}log_{7}(4)+log_{7}(2) \longrightarrow log_{7}(x)=log_{7}(2^{4/3}2)$
Step 2. Thus $ x=2^{7/3}$.
Step 3. Check answers, $x=2^{7/3}\approx5.040$ fits the original equation.