Find the binomial factors for the following trinomial and check using the FOIL method.

4m2 - 8m - 5

Question

Find the binomial factors for the following trinomial and check using the FOIL method.

4m2 - 8m - 5

anonymous · Answer

(2m-5)(2m+1)

Do you understand why?

anonymous · Answer

part of it. I think 2m comes from the GCF...am I right?

anonymous · Answer

Yes.

anonymous · Answer

could you show me how you did it? like, the steps?

anonymous · Answer

If you break the first part of the problem down, it is easier to see the outcome. (the factors)

anonymous · Answer

and sure.

anonymous · Answer

1. 4m^2 means that there are ms in both parts of the factors. But since it is 4 m^2 there must be more than one in each. Factors of four are 1 and 4 and 2 and 2. Since m multiplied by 4m did not work with the rest of the problem, we could not use it. How come it didn't work? Because it would make the middle value too large. 

Ex. it would be 4m^2 and you would have 19 or 20m in the middle.

anonymous · Answer

So then really the two first values of the factors have to add the the number of ms in the middle. So I used 2m and 2m. 

(2m.....) (2m.....) 

Since we knew that the last number had to multiply to -5, we knew that at least one of the two numbers had to be negative. If the two was negative, we would multiply the binomials to get 4m^2+8m-5. but if the five was negative, we would get the given trinomial. 

I know that is a lot of words, but trust me, it is not hard. Do you get it?

anonymous · Answer

And do you know foil?

anonymous · Answer

yes I do

anonymous · Answer

Okay so you understand pretty much everything I'm saying.

anonymous · Answer

yup lol just trying to scribble it out on paper atm