## Precalculus (6th Edition)

The given relation defines $y$ as a function of $x$. domain: $(-\infty, +\infty)$ range: $(-\infty, +\infty)$
For every value of $x$, the equation $y=2x-5$ gives only one value of $y$. This means that every value of $x$, $x$ is paired with only one value of $y$. Thus, the given relation defines $y$ as a function of $x$. The value of $x$ can be any real number so the domain is $(-\infty, +\infty)$. Since $x$ can be any real number and $y$ is five less than twice of $x$, then $y$ can be any real number as well. Thus, the range is $(-\infty, +\infty)$ .