Answer
$2^{4}=16$
Work Step by Step
From the definition of the logarithmic function on page 456, we know that $y=log_b{x}$ is equivalent to $b^{y}=x$ (for $x\gt0$, $b\gt0$, and $b\ne1$).
Therefore, $4=log_2{16}$ is equivalent to $2^{4}=16$ in exponential form.