Answer
$f(\frac{2}{3}) = \sqrt[3]{9} \approx 2.08$
Work Step by Step
Substitute $\frac{2}{3}$ to $x$ in the given function to have:
$f(x) = 3^x
\\f(\frac{2}{3}) = 3^{\frac{2}{3}}$
RECALL:
$a^{\frac{b}{c}}=\sqrt[c]{a^b}$
Use the rule above to have:
$f(\frac{2}{3}) = 3^{\frac{2}{3}}
\\f(\frac{2}{3}) = \sqrt[3]{3^2}
\\f(\frac{2}{3}) = \sqrt[3]{9} \approx 2.08$
