SOLUTION: Hello. I'm needing some help in completing each factorization. 6p^2-5p-4=( )(2p+1) Thanks!

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Question 184674: Hello.
I'm needing some help in completing each factorization.
6p^2-5p-4=( )(2p+1)
Thanks!

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Looking at the expression 6p%5E2-5p-4, we can see that the first coefficient is 6, the second coefficient is -5, and the last term is -4.


Now multiply the first coefficient 6 by the last term -4 to get %286%29%28-4%29=-24.


Now the question is: what two whole numbers multiply to -24 (the previous product) and add to the second coefficient -5?


To find these two numbers, we need to list all of the factors of -24 (the previous product).


Factors of -24:
1,2,3,4,6,8,12,24
-1,-2,-3,-4,-6,-8,-12,-24


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to -24.
1*(-24)
2*(-12)
3*(-8)
4*(-6)
(-1)*(24)
(-2)*(12)
(-3)*(8)
(-4)*(6)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient -5:


First NumberSecond NumberSum
1-241+(-24)=-23
2-122+(-12)=-10
3-83+(-8)=-5
4-64+(-6)=-2
-124-1+24=23
-212-2+12=10
-38-3+8=5
-46-4+6=2



From the table, we can see that the two numbers 3 and -8 add to -5 (the middle coefficient).


So the two numbers 3 and -8 both multiply to -24 and add to -5


Now replace the middle term -5p with 3p-8p. Remember, 3 and -8 add to -5. So this shows us that 3p-8p=-5p.


6p%5E2%2Bhighlight%283p-8p%29-4 Replace the second term -5p with 3p-8p.


%286p%5E2%2B3p%29%2B%28-8p-4%29 Group the terms into two pairs.


3p%282p%2B1%29%2B%28-8p-4%29 Factor out the GCF 3p from the first group.


3p%282p%2B1%29-4%282p%2B1%29 Factor out 4 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%283p-4%29%282p%2B1%29 Combine like terms. Or factor out the common term 2p%2B1

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Answer:


So 6p%5E2-5p-4 factors to %283p-4%29%282p%2B1%29.



So the missing factor is 3p-4