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

$3y^9\sqrt{10y}$
Getting the perfect factors and then extracting its root, the simplified form of the given expression, $\sqrt{90y^{19}} ,$ is \begin{array}{l}\require{cancel} \sqrt{9y^{18}\cdot 10y} \\\\= \sqrt{(3y^9)^2\cdot 10y} \\\\= 3y^9\sqrt{10y} .\end{array} Note that variables are assumed to represent positive real numbers.