Factorization by Middle Term Breaking

Example 1

$$\textup{Factorize } x^2+11x+28$$

\begin{align*} & x^2+11x+28\\ =\,\,& x^2+4x+7x+28\\ =\,\,& x(x+4)+7(x+4)\\ =\,\,& (x+4)(x+7)\\ \end{align*}