Factor $LaTeX: \displaystyle 20 x^{3} - 40 x^{2} - 28 x + 56$ .

Factoring out the GCF $LaTeX: \displaystyle 4$ from each term gives $LaTeX: \displaystyle 4(5 x^{3} - 10 x^{2} - 7 x + 14)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 5 x^{2}$ , gives $LaTeX: \displaystyle 5 x^{2}(x - 2)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle -7$ , gives $LaTeX: \displaystyle -7(x - 2)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle x - 2$ . This gives $LaTeX: \displaystyle 4[5 x^{2} \left(x - 2\right) -7 \cdot \left(x - 2\right)] = 4\left(x - 2\right) \left(5 x^{2} - 7\right)$ .