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

Factoring out the GCF $LaTeX: \displaystyle -4$ from each term gives $LaTeX: \displaystyle -4(7 x^{3} - 7 x^{2} + 5 x - 5)$ . Grouping the first two terms and factoring out their GCF, $LaTeX: \displaystyle 7 x^{2}$ , gives $LaTeX: \displaystyle 7 x^{2}(x - 1)$ . Grouping the last two terms and factoring out their GCF, $LaTeX: \displaystyle 5$ , gives $LaTeX: \displaystyle 5(x - 1)$ . The polynomial now has a common binomial factor of $LaTeX: \displaystyle x - 1$ . This gives $LaTeX: \displaystyle -4[7 x^{2} \left(x - 1\right) +5 \cdot \left(x - 1\right)] = -4\left(x - 1\right) \left(7 x^{2} + 5\right)$ .