## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$(x+1)(x+10)$
The 2 numbers whose product is $ac= 1(10)=10$ and whose sum is $b= 11$ are $\left\{ 1,10 \right\}.$ Using these two numbers to decompose the middle term of the given trinomial, $x^2+11x+10 ,$ then \begin{array}{l}\require{cancel} x^2+x+10x+10 \\\\= (x^2+x)+(10x+10) \\\\= x(x+1)+10(x+1) \\\\= (x+1)(x+10) .\end{array}