SOLUTION: factor x^2+7x+10=0

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Question 145612: factor x^2+7x+10=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Looking at x%5E2%2B7x%2B10 we can see that the first term is x%5E2 and the last term is 10 where the coefficients are 1 and 10 respectively.

Now multiply the first coefficient 1 and the last coefficient 10 to get 10. Now what two numbers multiply to 10 and add to the middle coefficient 7? Let's list all of the factors of 10:



Factors of 10:
1,2,5,10

-1,-2,-5,-10 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to 10
1*10
2*5
(-1)*(-10)
(-2)*(-5)

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


Now which of these pairs add to 7? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 7

First NumberSecond NumberSum
1101+10=11
252+5=7
-1-10-1+(-10)=-11
-2-5-2+(-5)=-7



From this list we can see that 2 and 5 add up to 7 and multiply to 10


Now looking at the expression x%5E2%2B7x%2B10, replace 7x with 2x%2B5x (notice 2x%2B5x adds up to 7x. So it is equivalent to 7x)

x%5E2%2Bhighlight%282x%2B5x%29%2B10


Now let's factor x%5E2%2B2x%2B5x%2B10 by grouping:


%28x%5E2%2B2x%29%2B%285x%2B10%29 Group like terms


x%28x%2B2%29%2B5%28x%2B2%29 Factor out the GCF of x out of the first group. Factor out the GCF of 5 out of the second group


%28x%2B5%29%28x%2B2%29 Since we have a common term of x%2B2, we can combine like terms

So x%5E2%2B2x%2B5x%2B10 factors to %28x%2B5%29%28x%2B2%29


So this also means that x%5E2%2B7x%2B10 factors to %28x%2B5%29%28x%2B2%29 (since x%5E2%2B7x%2B10 is equivalent to x%5E2%2B2x%2B5x%2B10)



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Answer:
So x%5E2%2B7x%2B10 factors to %28x%2B5%29%28x%2B2%29