SOLUTION: Factor. a^2 + 16a + 64

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Question 132424: Factor.
a^2 + 16a + 64

Found 2 solutions by jim_thompson5910, edjones:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!

Looking at we can see that the first term is and the last term is where the coefficients are 1 and 64 respectively.

Now multiply the first coefficient 1 and the last coefficient 64 to get 64. Now what two numbers multiply to 64 and add to the middle coefficient 16? Let's list all of the factors of 64:



Factors of 64:
1,2,4,8,16,32

-1,-2,-4,-8,-16,-32 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to 64
1*64
2*32
4*16
8*8
(-1)*(-64)
(-2)*(-32)
(-4)*(-16)
(-8)*(-8)

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


Now which of these pairs add to 16? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 16

First NumberSecond NumberSum
1641+64=65
2322+32=34
4164+16=20
888+8=16
-1-64-1+(-64)=-65
-2-32-2+(-32)=-34
-4-16-4+(-16)=-20
-8-8-8+(-8)=-16



From this list we can see that 8 and 8 add up to 16 and multiply to 64


Now looking at the expression , replace with (notice adds up to . So it is equivalent to )




Now let's factor by grouping:


Group like terms


Factor out the GCF of out of the first group. Factor out the GCF of out of the second group


Since we have a common term of , we can combine like terms

So factors to


So this also means that factors to (since is equivalent to )


note: is equivalent to since the term occurs twice. So also factors to



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Answer:
So factors to

Answer by edjones(8007)   (Show Source): You can put this solution on YOUR website!
(a+8)^2
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