Factor $LaTeX: \displaystyle 28 x^{3} - 40 x^{2} - 49 x + 70$ .

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