# What is -4 square root of 90 + 2 square root of 160?

Apr 30, 2018

$- 4 \sqrt{10}$

#### Explanation:

-4sqrt(90)+ 2sqrt(160) = ?

Assuming this to be the question(unfortunately, the lack of math symbols makes it ambiguous), the answer shall be:

$= - 4 \left(3\right) \sqrt{10} + 2 \left(4\right) \sqrt{10}$
^What I've done here is $\sqrt{a b} = \sqrt{a} \sqrt{b}$ (9 times 10 and 16 times 10 respectively)

$= - 12 \sqrt{10} + 8 \sqrt{10}$
$= - 4 \sqrt{10}$

Apr 30, 2018

$- 4 \setminus \sqrt{90} + 2 \setminus \sqrt{160}$ = -12 sqrt{10} + 8 sqrt{10}  $= - 4 \sqrt{10}$

#### Explanation:

$- 4 \setminus \sqrt{90} + 2 \setminus \sqrt{160}$

$- 4 \setminus \sqrt{{3}^{2} \cdot 10} + 2 \setminus \sqrt{{4}^{2} \cdot 10}$

= -12 sqrt{10} + 8 sqrt{10}

$= - 4 \sqrt{10}$

Why does it say just asked when it's two years old?