#### Answer

$\log_2{16}=4$

#### Work Step by Step

Let
$x=\log_2{16}.$
RECALL:
$\log_{a}{y} = b \longleftrightarrow a^b = y$
Use the definition above to convert the equation to an exponential equation and have
$2^x=16.$
Write each side in base 2 to have
$2^x=2^4.$
The bases are the same, so the exponents must be equal. Thus,
$x=4$ and so $\log_2{16}=4.$