#### Answer

$(m-2)(n+5)$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
Group the terms of the given expression, $
mn-2n+5m-10
,$ such that the factored form of the groupings will result to a factor that is common to the entire expression. Then, factor the $GCF$ in each group. Finally, factor the $GCF$ of the entire expression.
$\bf{\text{Solution Details:}}$
Grouping the first and second terms and the third and fourth terms, the given expression is equivalent to
\begin{array}{l}\require{cancel}
(mn-2n)+(5m-10)
.\end{array}
Factoring the $GCF$ in each group results to
\begin{array}{l}\require{cancel}
n(m-2)+5(m-2)
.\end{array}
Factoring the $GCF=
(m-2)
$ of the entire expression above results to
\begin{array}{l}\require{cancel}
(m-2)(n+5)
.\end{array}