## Introductory Algebra for College Students (7th Edition)

$i\sqrt{19}$
Using the properties of radicals and that $i=\sqrt{-1}$, then the given expression, $\sqrt{-19} ,$ is equivalent to \begin{array}{l}\require{cancel} \sqrt{-1}\cdot\sqrt{19} \\\\= i\cdot\sqrt{19} \\\\= i\sqrt{19} .\end{array}