Factor $LaTeX: \displaystyle - 90 x^{3} - 60 x^{2} - 45 x - 30$ .

Factoring out the GCF $LaTeX: \displaystyle -15$ from each term gives $LaTeX: \displaystyle -15(6 x^{3} + 4 x^{2} + 3 x + 2)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 2 x^{2}$ , gives $LaTeX: \displaystyle 2 x^{2}(3 x + 2)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 1$ , gives $LaTeX: \displaystyle 1(3 x + 2)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 3 x + 2$ . This gives $LaTeX: \displaystyle -15[2 x^{2} \left(3 x + 2\right) +1 \cdot \left(3 x + 2\right)] = -15\left(3 x + 2\right) \left(2 x^{2} + 1\right)$ .