## Intermediate Algebra (12th Edition)

$y \text{ is a function of }x \\\text{Domain: } [3,\infty)$
$\bf{\text{Solution Outline:}}$ To determine if the given equation, $y=\sqrt{x-3} ,$ is a function, check if $x$ is unique for every value of $y.$ To find the domain, find the set of all possible values of $x.$ $\bf{\text{Solution Details:}}$ For each value of $x,$ subtracting it by $3$ and getting the square root will produce a single value of $y.$ Hence, $y$ is a function of $x.$ The radicand, $x-3,$ of a radical with an even index cannot be negative. Hence, \begin{array}{l}\require{cancel} x-3\ge0 \\\\ x\ge3 .\end{array} The given equation has the following characteristics: \begin{array}{l}\require{cancel} y \text{ is a function of }x \\\text{Domain: } [3,\infty) .\end{array}