# How do you simplify -sqrt40?

Apr 17, 2018

$- 2 \sqrt{10}$

#### Explanation:

$- \sqrt{40} \rightarrow$ Look for any perfect squares

$- \sqrt{4 \cdot 10} \rightarrow$ $4$ is a perfect square

$- 2 \sqrt{10}$

Apr 17, 2018

$- 2 \sqrt{10}$

#### Explanation:

Note here that:

$\sqrt{a b} = {\left(a b\right)}^{\frac{1}{2}} \implies {a}^{\frac{1}{2}} \cdot {b}^{\frac{1}{2}}$

Factor $40$

$\implies - \sqrt{4 \cdot 10}$

$\implies - {\left(4\right)}^{\frac{1}{2}} \cdot {10}^{\frac{1}{2}}$

$\implies - \sqrt{4} \cdot \sqrt{10}$

$\implies - 2 \sqrt{10}$

Apr 17, 2018

$- 2 \sqrt{10}$

#### Explanation:

$- \sqrt{40}$ is the same thing as $- \sqrt{4 \cdot 10}$. Since 4 is a perfect square, (2*2=4) or ($\sqrt{4} = 2$), you can take four out of the radical to simplify to $- 2 \sqrt{10}$.