## Introductory Algebra for College Students (7th Edition)

$(x+1)(x+12)$
The given expression, $x^2+13x+12 ,$ has $c= 12$ and $b= 13 .$ The possible factors of $c$ are $\{ 1,12 \} ,\{ 2,6 \} ,\{ 3,4 \} ,\{ -1,-12 \} ,\{ -2,-6 \} ,\{ -3,-4 \}$. Among these factors, the pair whose sum is equal to $b$ is $\{ 1,12 \}.$ Hence, the factored form is \begin{array}{l}\require{cancel} (x+1)(x+12) .\end{array}