Factor $LaTeX: \displaystyle 20 x^{3} + 8 x^{2} - 70 x - 28$ .

Factoring out the GCF $LaTeX: \displaystyle 2$ from each term gives $LaTeX: \displaystyle 2(10 x^{3} + 4 x^{2} - 35 x - 14)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 2 x^{2}$ , gives $LaTeX: \displaystyle 2 x^{2}(5 x + 2)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle -7$ , gives $LaTeX: \displaystyle -7(5 x + 2)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 5 x + 2$ . This gives $LaTeX: \displaystyle 2[2 x^{2} \left(5 x + 2\right) -7 \cdot \left(5 x + 2\right)] = 2\left(5 x + 2\right) \left(2 x^{2} - 7\right)$ .