#### Answer

$5\left( 7a+11c+1 \right)$

#### Work Step by Step

The $GCF$ of the given expression, $
35a+55c+5
,$ is $5,$ since it is the highest number that can evenly divide (no remainder) all the terms. Factoring the $GCF$ results to
\begin{array}{l}\require{cancel}
5\left( \dfrac{35a}{5}+\dfrac{55c}{5}+\dfrac{5}{5} \right)
\\\\=
5\left( 7a+11c+1 \right)
.\end{array}