Question

how do you factor out the coefficient of a variable?

Answer 1

You divide by the coefficient. 

Let's say I have 2x.  To get rid of the coefficient, I have to get rid of that 2, which basically means turn the coefficient of the variable into a 1. How do I do that? We divide by 2 but keep it equivalent. That probably makes no sense, so let me show you:

2x is the same thing as 2(x). See? Now the 2 and the x are separated, but the expression is still the same! More examples:

5x   >   5(x)

10x  >  10(x)

Here's a tricky one:

$10x^2$  >  10x(x)

I hope this helped!