# How do you factor 5a - 20 ?

May 15, 2016

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

#### Explanation:

We begin with $5 a - 20$. The first thing I noticed with this problem is that both $5$ and $20$ are divisible by $5$. That means that we can factor out a $5$ from both components, which leaves us with $5 \left(a - 4\right)$.

There, that's it. $5 \left(a - 4\right)$ cannot be factored any further.

May 15, 2016

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

#### Explanation:

To factor this expression, tell yourself
"I need a number (or variable) that 'go into' both 5a and -20.
Well, 5 is a factor of 5 and -20.
So 5 go into 5a (1a times).
That sounds confusing, but remember, 5 go into 5 one time, but in algebra, you don't normally write the number 1 in coefficient, so it's just 'a'. 5 can't go into 'a' because a is just a single variable.
5 can go into 20, 4 times.
So now our final answer will be 5(a-4).
Hopefully this make sense!