How do you multiply 3\sqrt { 5} \cdot 3\sqrt { 5}?

Feb 23, 2017

$45$

Explanation:

separate the integers from the radicals.

$\Rightarrow \textcolor{red}{3} \times \textcolor{b l u e}{\sqrt{5}} \times \textcolor{red}{3} \times \textcolor{b l u e}{\sqrt{5}}$

$= \left(\textcolor{red}{3} \times \textcolor{red}{3}\right) \times \left(\textcolor{b l u e}{\sqrt{5}} \times \textcolor{b l u e}{\sqrt{5}}\right)$

$= 9 \times 5$

$= 45$