Factor $LaTeX: \displaystyle 40 x^{3} - 35 x^{2} - 32 x + 28$ .

Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 5 x^{2}$ , gives $LaTeX: \displaystyle 5 x^{2}(8 x - 7)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle -4$ , gives $LaTeX: \displaystyle -4(8 x - 7)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle 8 x - 7$ . This gives $LaTeX: \displaystyle 5 x^{2} \left(8 x - 7\right) -4 \cdot \left(8 x - 7\right) = \left(8 x - 7\right) \left(5 x^{2} - 4\right)$ .