# Thread: Quadratics Factoring

1. ## Quadratics Factoring

I'm not good at quadratics at all, especially factoring simple problems...

ex. factor 8k2 - 6k - 5

My attempt:

ax2 + bx + c = 0

ac = -40 b = -6

find two numbers that the product is -40 and sum is -6

+4 and -10

8k2 + 4k - 10k - 5

group like terms and then factor: This is the step I do not know how to do...

The answer is (4k - 5)(2k - 1)

Also, I have know clue where to start on this one:

0.4m2 + 0.6m -1.8

2. ## Re: Quadratics Factoring

Hey Mathnood768.

Hint: Try using the quadratic formula to get f(k) = 0 to solve for k (k1 and k2) and then use the factorization (k - k1)(k - k2) as your factorization and clean it up.

This is equivalent and it will work for any values of your quadratic.

3. ## Re: Quadratics Factoring

For the second function rewrite the same as equation in simple form. we will get
4m^2+6m-18=0 OR
2m^2 + 3m - 9 = 0
Now proceed as earlier to split the middle term

4. ## Re: Quadratics Factoring

I need to do it the way I wrote down though, I did not learn about quadratic formula. It would be helpful if you could actually use the example I put out.

5. ## Re: Quadratics Factoring

Originally Posted by ibdutt
For the second function rewrite the same as equation in simple form. we will get
4m^2+6m-18=0 OR
2m^2 + 3m - 9 = 0
Now proceed as earlier to split the middle term
Now the product ac = -18 and the factors of -18 such that the sum is 3 are 6 and - 3
So we have
2m^2 + 6m - 3m - 9 = 0
(2m-3)(m+3)=0
That will give m = 3/2 and m = -3