## Precalculus (6th Edition) Blitzer

$y$ is not a function of $x$
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 $x$.