# What is (-7 square root of 3)(-4 square root of 10)?

Sep 22, 2015

$28 \sqrt{30}$

#### Explanation:

All we do here is multiply the stuff outside the square roots and the stuff inside the square roots.

$\left(- 7 \sqrt{3}\right) \left(- 4 \sqrt{10}\right)$

$\left(- 7 \cdot - 4\right) \left(\sqrt{3} \cdot \sqrt{10}\right)$ (because -7 and -4 are normal numbers, so we combine them; $\sqrt{10}$ and $\sqrt{3}$ are special, so we combine them separately).

$= 28 \sqrt{30}$ (simplifying; $\sqrt{3} \cdot \sqrt{10} = \sqrt{10 \cdot 3} = \sqrt{30}$)