Factor $LaTeX: \displaystyle 72 x^{3} + 90 x^{2} + 16 x + 20$ .

Factoring out the GCF $LaTeX: \displaystyle 2$ from each term gives $LaTeX: \displaystyle 2(36 x^{3} + 45 x^{2} + 8 x + 10)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 9 x^{2}$ , gives $LaTeX: \displaystyle 9 x^{2}(4 x + 5)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 2$ , gives $LaTeX: \displaystyle 2(4 x + 5)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 4 x + 5$ . This gives $LaTeX: \displaystyle 2[9 x^{2} \left(4 x + 5\right) +2 \cdot \left(4 x + 5\right)] = 2\left(4 x + 5\right) \left(9 x^{2} + 2\right)$ .