How do you factor 18b^3-36b^2-9?

Jul 2, 2018

color(blue)(=> 9 * (2b^3 - 4b^2 - 1)
$18 {b}^{3} - 36 {b}^{2} - 9$
$\implies 9 \cdot 2 \cdot {b}^{3} - 9 \cdot 2 \cdot 2 \cdot {b}^{2} - 9$
$\implies 9 \cdot \left(2 {b}^{3} - 4 {b}^{2} - 1\right)$