# Question #c2eb1

Mar 14, 2017

It doesn't simplify nicely.

#### Explanation:

You could call $- \sqrt{42} - \sqrt{42}$
$- 2 \sqrt{42}$ if you wanted, the same as calling $- x - x$
negative $- 2 x$.
Then, if you think of $2$ as $\sqrt{4}$, then you could call it $- \sqrt{4} \sqrt{42}$
Using the rule $\sqrt{a} \sqrt{b} = \sqrt{a \cdot b}$, you end up with $- \sqrt{168}$. However, that doesn't simplify nicely, so that's about as far as you can go without getting a nasty decimal number (-12.9614814).
In fact, you probably would want to leave it as $- 2 \sqrt{42}$, since that is the simplest radical possible.