## College Algebra 7th Edition

$y$ is NOT a function of $x$
Take the fourth root of each side of the equation to obtain: $x=y^4 \\\pm\sqrt[4]{x} = \sqrt[4]{y^4} \\\pm \sqrt[4]{x} = y$ Note that in the last equation above, for every value of $x$, there corresponds two different value of $y$. Thus, the $y$ is not a function of $x$.