## Intermediate Algebra (12th Edition)

$\bf{\text{Solution Outline:}}$ The given expression, $9r^2+100 ,$ is prime. $\bf{\text{Solution Details:}}$ A binomial can be factored if the $GCF$ between its terms is not $1$, or if it is a difference of $2$ squares, or if it is a sum/difference of $2$ cubes. The $GCF$ of the terms of the given binomial is $1.$ It is also not a differene of two squares because it uses a plus sign between its terms. It is also not a difference of $2$ cubes because its terms are not perfect cubes. Hence, the given expression is $\text{ not factorable .}$