Answer
$y$ is not a function of $x$
Work Step by Step
Solve for $y$ in terms of $x$ to obtain:
$y^2=-x+5
\\y = \pm \sqrt{-x+5}$
Note that each value of $x$ within the relation's domain will give one or two values of $y$.
Thus, the given equation does not represent $y$ as a function of $x$.
