Question

How do you evaluate `sqrt5-3sqrt5`?

Answer 1

`-2sqrt5`

Explanation:

First of all:

`sqrt5` is the same as saying `1sqrt5` since anything times `1` is itself.

So we can change the equation a little:

`1 sqrt5 - 3sqrt5`

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 `sqrt5` in the answer:

`1sqrt5 - 3 sqrt5 = -2sqrt5`