#### Answer

$(m+6)(m+7)$

#### Work Step by Step

Using the factoring of trinomials in the form $x^2+bx+c,$ the given expression, $
m^2+13m+42
,$ has $c$ equal to $
42
$ and $b$ equal to $
13
.$
The two numbers that give a product of $c$ and a sum of $b$ are $\{
6,7
\}.$ Hence, the factored form of the expression above is
\begin{array}{l}\require{cancel}
(m+6)(m+7)
.\end{array}