Answer
$7$
Work Step by Step
RECALL
$y=\log{x} \longleftrightarrow 10^y=x.$
Let $y=\log{10^7}.$
Use the definition above to obtain
$y=\log{10^7} \longrightarrow 10^y=10^7.$
Use the rule "if $a^x=a^y$, then $x=y$" to obtain
$y=7.$
Therefore,
$\log{10^7} = 7.$
