#### Answer

$\log_3{9}=2$

#### Work Step by Step

Let
$x=\log_3{9}.$
RECALL:
$\log_{a}{y} = b \longleftrightarrow a^b = y.$
Use the definition above to convert the equation to an exponential equation and have
$3^x=9.$
Write each side in base 3 to have
$3^x=3^2.$
The bases are the same, so the exponents must be equal. Thus,
$x=2.$
Therefore $\log_3{9}=2$.