Answer
$4$
Work Step by Step
The domain of the variable requires that $x+6>0$, which means that $x>-6$.
Recall:
$y=\log_a{x} \implies a^y=x$
Thus,
$\log(x+6)= 1 \\
\implies 10^1=x+6\\
\implies 10=x+6$
Solve the equation to obtain:
\begin{align*}
10-6&=x\\
4&=x
\end{align*}