Answer
$12$
Work Step by Step
Substituting $a=
-5
$ and $b=
9
$, the given expression, $
-2a+\dfrac{a-b}{a-2}
,$ evaluates to
\begin{array}{l}\require{cancel}
-2(-5)+\dfrac{-5-9}{-5-2}
\\\\=
10+\dfrac{-14}{-7}
\\\\=
10+2
\\\\=
12
.\end{array}