SOLUTION: Factor: x^2+5x+6

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Question 125883: Factor:
x^2+5x+6

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

Looking at 1x%5E2%2B5x%2B6 we can see that the first term is 1x%5E2 and the last term is 6 where the coefficients are 1 and 6 respectively.

Now multiply the first coefficient 1 and the last coefficient 6 to get 6. Now what two numbers multiply to 6 and add to the middle coefficient 5? Let's list all of the factors of 6:



Factors of 6:
1,2,3,6

-1,-2,-3,-6 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to 6
1*6
2*3
(-1)*(-6)
(-2)*(-3)

note: remember two negative numbers multiplied together make a positive number


Now which of these pairs add to 5? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 5

First NumberSecond NumberSum
161+6=7
232+3=5
-1-6-1+(-6)=-7
-2-3-2+(-3)=-5



From this list we can see that 2 and 3 add up to 5 and multiply to 6


Now looking at the expression 1x%5E2%2B5x%2B6, replace 5x with 2x%2B3x (notice 2x%2B3x adds up to 5x. So it is equivalent to 5x)

1x%5E2%2Bhighlight%282x%2B3x%29%2B6


Now let's factor 1x%5E2%2B2x%2B3x%2B6 by grouping:


%281x%5E2%2B2x%29%2B%283x%2B6%29 Group like terms


x%28x%2B2%29%2B3%28x%2B2%29 Factor out the GCF of x out of the first group. Factor out the GCF of 3 out of the second group


%28x%2B3%29%28x%2B2%29 Since we have a common term of x%2B2, we can combine like terms

So 1x%5E2%2B2x%2B3x%2B6 factors to %28x%2B3%29%28x%2B2%29


So this also means that 1x%5E2%2B5x%2B6 factors to %28x%2B3%29%28x%2B2%29 (since 1x%5E2%2B5x%2B6 is equivalent to 1x%5E2%2B2x%2B3x%2B6)



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Answer:
So x%5E2%2B5x%2B6 factors to %28x%2B3%29%28x%2B2%29