Answer
$(x+1)(x+10)$
Work Step by Step
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}