Factor $LaTeX: \displaystyle 9 x^{3} + 72 x^{2} + 5 x + 40$ .

Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 9 x^{2}$ , gives $LaTeX: \displaystyle 9 x^{2}(x + 8)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 5$ , gives $LaTeX: \displaystyle 5(x + 8)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle x + 8$ . This gives $LaTeX: \displaystyle 9 x^{2} \left(x + 8\right) +5 \cdot \left(x + 8\right) = \left(x + 8\right) \left(9 x^{2} + 5\right)$ .