Answer
$y$ is a function of $x$
Work Step by Step
Take the cube root of both sides of the equation to obtain:
$x=y^3
\\\sqrt[3]{x} = \sqrt[3]{y^3}
\\\sqrt[3]{x} = y$
In the last equation above,for every $x$ value, there corresponds one value of $y$.
Thus, the given equation defines $y$ as a function of $x$.