Answer
$ (a+2)(b+7)$
Work Step by Step
$ab+7a+2b+14 = a(b+7) + 2(b+7)$
The binomial $(b+7)$ is present in both terms and is the greatest common factor. We use the distributive property to factor out $(b+7)$
$ab+7a+2b+14 = a(b+7) + 2(b+7) = (a+2)(b+7)$