Chapter 2 - Linear and Quadratic Functions - Section 2.6 Building Quadratic Models from Verbal Descriptions and from Data - 2.6 Assess Your Understanding - Page 174: 32

$15i$

Note that $\sqrt{-225}=\sqrt{-1( 225)}$ Use the Product Rule $\sqrt{a b}=\sqrt{a} \times \sqrt{b}$ to obtain: $\begin{aligned} \sqrt{-1(225)} &=\sqrt{-1} \times \sqrt{225} \\ &=i \times \sqrt{15^{2}} \\ &=i \times 15 \\ &=15 i \end{aligned}$