SOLUTION: 2a(a – 5) + 4(a – 5) how do I work this expression out to simplest form. I need to learn how to explain each step of showing work. How do I do it? Thanks~

Algebra ->  Expressions-with-variables -> SOLUTION: 2a(a – 5) + 4(a – 5) how do I work this expression out to simplest form. I need to learn how to explain each step of showing work. How do I do it? Thanks~       Log On


   

Question 846630: 2a(a – 5) + 4(a – 5) how do I work this expression out to simplest form.
I need to learn how to explain each step of showing work. How do I do it?

Thanks~

Answer by josh_jordan(263) About Me  (Show Source):
You can put this solution on YOUR website!
If you required to express in simplest factor form, you can first factor out (a - 5) from the expression, giving you

(a - 5)(2a + 4)

If you are required to expand the factors and express in polynomial form, you would then use the FOIL method on (a - 5)(2a + 4):

(a x 2a) + (4 x a) + (-5 x 2a) + (-5 x 4) =

2a^2 + 4a - 10a - 20

Combining like terms gives us:

2a^2 - 6a - 20