#### Answer

$|q|$

#### Work Step by Step

As shown on page 437, $\sqrt[n] a^{n}=|a|$ when $n$ is an even positive integer.
In this case, we know that $\sqrt (-q)^{2}$ is equivalent to $\sqrt[2] (-q)^{2}$, since we are taking the square root.
Therefore, we know that $\sqrt (-q)^{2}=\sqrt[2] (-q)^{2}=|-q|=|q|$.