#### Answer

$-12$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
Substitute $x=-12,$ to evaluate the given expression, $
-(-x)
.$
$\bf{\text{Solution Details:}}$
Substituting $x=-12,$ the given expression evaluates to
\begin{array}{l}\require{cancel}
-(-x)
\\\\=
-(-(-12))
\\\\=
-(12)
\\\\=
-12
.\end{array}