# How do you factor 4a^2 - 5ab ?

Oct 2, 2017

$a \left(4 a - 5 b\right)$

#### Explanation:

To factor a number or expression means to write it as the product of its prime factors.

In Algebra, always check for a common factor first.

$4 {a}^{2} - 5 a b \text{ } \leftarrow H C F = a$

Divide $a$ out of each term:

$= a \left(4 a - 5 b\right) \text{ } \leftarrow$ there are now 2 factors

Oct 2, 2017

$a \left(4 a - 5 b\right)$
$\text{there is a "color(blue)"common factor ""of a in both terms}$
$\text{which can be taken out}$
$\Rightarrow 4 {a}^{2} - 5 a b = a \left(4 a - 5 b\right) \leftarrow \text{ factored form}$