Answer
$x$ is in the domain $(0,\infty).$
Work Step by Step
The definition of the logarithm says that the logarithm ($y$) is the exponent that indicates the power to which the base number ($a$) should be raised to get a given number($x$). e.g. $\log_5{25}=2$ because $5^2=25$.
The logarithmic function is a function (e.g. $y = \log_a {x}$) which is the inverse of an exponential function (e.g. of $y = a^x$) . $a>0, a\ne1 $, $x>0$.
We can only take the logarithm of a positive number, independent from the base, hence in order for $\log_a {x}$ to be defined, $x$ is in the domain $(0,\infty).$
