Answer
$22$
Work Step by Step
Substituting $a=
-1
$ and $b=
5
$, the given expression, $
5a+6b-7a-2b
,$ evaluates to
\begin{array}{l}\require{cancel}
5(-1)+6(5)-7(-1)-2(5)
\\\\=
-5+30+7-10
\\\\=
25+7-10
\\\\=
32-10
\\\\=
22
.\end{array}