Answer
$x=\log_{4}y$
Work Step by Step
From the definition of a logarithmic function, we have:
$\quad \log_{b}x=y\quad $ means $\quad b^{y}=x$
Here, $b=4$, and $x$ and $y$ have exchanged places.
$y=b^{x}\quad\Leftrightarrow\quad x=\log_{b}y$
$x=\log_{4}y$
