Factor $LaTeX: \displaystyle - 18 x^{3} - 6 x^{2} - 45 x - 15$ .

Factoring out the GCF $LaTeX: \displaystyle -3$ from each term gives $LaTeX: \displaystyle -3(6 x^{3} + 2 x^{2} + 15 x + 5)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 2 x^{2}$ , gives $LaTeX: \displaystyle 2 x^{2}(3 x + 1)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 5$ , gives $LaTeX: \displaystyle 5(3 x + 1)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 3 x + 1$ . This gives $LaTeX: \displaystyle -3[2 x^{2} \left(3 x + 1\right) +5 \cdot \left(3 x + 1\right)] = -3\left(3 x + 1\right) \left(2 x^{2} + 5\right)$ .