#### Answer

$y \text{ is a function of }x
\\\text{Domain: }
(-\infty,\infty)$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
To determine if the given equation, $
y=x^2
,$ is a function, check if every value of $x$ will produce a different value of $y.$
To find the domain, find the set of all possible values of $x.$
$\bf{\text{Solution Details:}}$
For each value of $x,$ squaring it will produce a different value of $y.$ Hence, $y$ is a function of $x.$
The variable $x$ can be replaced with any number. Hence, the domain is the set of all real numbers.
Hence, the given equation has the following characteristics:
\begin{array}{l}\require{cancel}
y \text{ is a function of }x
\\\text{Domain: }
(-\infty,\infty)
.\end{array}