Factor $LaTeX: \displaystyle - 25 x^{3} + 45 x^{2} + 20 x - 36$ .

Factoring out the GCF $LaTeX: \displaystyle -1$ from each term gives $LaTeX: \displaystyle -(25 x^{3} - 45 x^{2} - 20 x + 36)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 5 x^{2}$ , gives $LaTeX: \displaystyle 5 x^{2}(5 x - 9)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle -4$ , gives $LaTeX: \displaystyle -4(5 x - 9)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 5 x - 9$ . This gives $LaTeX: \displaystyle -1[5 x^{2} \left(5 x - 9\right) -4 \cdot \left(5 x - 9\right)] = -\left(5 x - 9\right) \left(5 x^{2} - 4\right)$ .