# How do you evaluate sqrt5-3sqrt5?

Apr 9, 2018

$- 2 \sqrt{5}$

#### Explanation:

First of all:

$\sqrt{5}$ is the same as saying $1 \sqrt{5}$ since anything times $1$ is itself.

So we can change the equation a little:

$1 \sqrt{5} - 3 \sqrt{5}$

Since these are being multiplied by the same square root, we can combine the numbers outside the radicals (sqrt signs) by subtracting $1 - 3$ and leaving the $\sqrt{5}$ in the answer:

$1 \sqrt{5} - 3 \sqrt{5} = - 2 \sqrt{5}$