How do you factor the expression 21x^2 - 22x - 8?

Mar 5, 2016

$= \left(3 x - 4\right) \left(7 x + 2\right)$
$21 {x}^{2} - 22 x - 8$
$= 21 {x}^{2} - 28 x + 6 x - 8$
$= 7 x \left(3 x - 4\right) + 2 \left(3 x - 4\right)$
$= \left(3 x - 4\right) \left(7 x + 2\right)$