# How do you factor  3a^2 - 6ab +2a - 4b?

Jun 26, 2016

=$\left(3 a + 2\right) \left(a - 2 b\right)$

#### Explanation:

When there are 4 or more terms in an expression, group them.
Make sure there is a + sign between the groups.

$3 {a}^{2} - 6 a b + 2 a - 4 b \text{ can be grouped as}$:

=$\left(3 {a}^{2} - 6 a b\right) + \left(2 a - 4 b\right) \text{ find a factor in each pair}$

=$3 a \left(a - 2 b\right) + 2 \left(a - 2 b\right) \text{ there is a common bracket}$

=$\left(a - 2 b\right) \left(3 a + 2\right)$

OR:
$3 {a}^{2} - 6 a b + 2 a - 4 b \text{ can be grouped as}$:

$\left(3 {a}^{2} + 2 a\right) + \left(- 6 a b - 4 b\right)$:

Taking out different factors will still give the same answer as the first method. NOte that the signs in the second term will change.

$\left(3 {a}^{2} + 2 a\right) + \left(- 6 a b - 4 b\right)$

=$a \left(3 a + 2\right) - 2 b \left(3 a + 2\right)$

=$\left(3 a + 2\right) \left(a - 2 b\right)$