How do you factor completely 4x^2 - 12x + 8?

Apr 6, 2016

$4 \left(x - 1\right) \left(x - 2\right)$

Explanation:

Given
$\textcolor{w h i t e}{\text{XXX}} 4 {x}^{2} - 12 x + 8$

Extract the constant factor of $4$
$\textcolor{w h i t e}{\text{XXX}} = 4 \left({x}^{2} - 3 x + 2\right)$

Since $\left(- 1\right) + \left(- 2\right) = \left(- 3\right)$ and $\left(- 1\right) \times \left(- 2\right) = 2$
$\textcolor{w h i t e}{\text{XXX}} = 4 \left(x - 1\right) \left(x - 2\right)$