Factor $LaTeX: \displaystyle 9 x^{3} + 8 x^{2} + 90 x + 80$ .

Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle x^{2}$ , gives $LaTeX: \displaystyle x^{2}(9 x + 8)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 10$ , gives $LaTeX: \displaystyle 10(9 x + 8)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 9 x + 8$ . This gives $LaTeX: \displaystyle x^{2} \left(9 x + 8\right) +10 \cdot \left(9 x + 8\right) = \left(9 x + 8\right) \left(x^{2} + 10\right)$ .