Answer
$\log_a x$
Work Step by Step
Using the properties of logarithms, the given expression, $
\log_a x^2-2\log_a \sqrt{x}
,$ is equivalent to
\begin{array}{l}\require{cancel}
\log_a x^2-\log_a \left( \sqrt{x} \right)^2
\\\\=
\log_a x^2-\log_a x
\\\\=
\log_a \dfrac{x^2}{x}
\\\\=
\log_a x
.\end{array}