Factor $LaTeX: \displaystyle - 40 x^{3} + 12 x^{2} + 50 x - 15$ .

Factoring out the GCF $LaTeX: \displaystyle -1$ from each term gives $LaTeX: \displaystyle -(40 x^{3} - 12 x^{2} - 50 x + 15)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 4 x^{2}$ , gives $LaTeX: \displaystyle 4 x^{2}(10 x - 3)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle -5$ , gives $LaTeX: \displaystyle -5(10 x - 3)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 10 x - 3$ . This gives $LaTeX: \displaystyle -1[4 x^{2} \left(10 x - 3\right) -5 \cdot \left(10 x - 3\right)] = -\left(10 x - 3\right) \left(4 x^{2} - 5\right)$ .