SOLUTION: Factor; 4a^2-4a+1 I did it just like by this problem; a^2-9= a^2-3^2= (a+3)(a-3, but it was wrong.

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: Factor; 4a^2-4a+1 I did it just like by this problem; a^2-9= a^2-3^2= (a+3)(a-3, but it was wrong.       Log On


   



Question 147362: Factor; 4a^2-4a+1
I did it just like by this problem; a^2-9= a^2-3^2= (a+3)(a-3, but it was wrong.

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

Looking at 4a%5E2-4a%2B1 we can see that the first term is 4a%5E2 and the last term is 1 where the coefficients are 4 and 1 respectively.

Now multiply the first coefficient 4 and the last coefficient 1 to get 4. Now what two numbers multiply to 4 and add to the middle coefficient -4? Let's list all of the factors of 4:



Factors of 4:
1,2

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

These factors pair up and multiply to 4
1*4
2*2
(-1)*(-4)
(-2)*(-2)

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


Now which of these pairs add to -4? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -4

First NumberSecond NumberSum
141+4=5
222+2=4
-1-4-1+(-4)=-5
-2-2-2+(-2)=-4



From this list we can see that -2 and -2 add up to -4 and multiply to 4


Now looking at the expression 4a%5E2-4a%2B1, replace -4a with -2a%2B-2a (notice -2a%2B-2a adds up to -4a. So it is equivalent to -4a)

4a%5E2%2Bhighlight%28-2a%2B-2a%29%2B1


Now let's factor 4a%5E2-2a-2a%2B1 by grouping:


%284a%5E2-2a%29%2B%28-2a%2B1%29 Group like terms


2a%282a-1%29-1%282a-1%29 Factor out the GCF of 2a out of the first group. Factor out the GCF of -1 out of the second group


%282a-1%29%282a-1%29 Since we have a common term of 2a-1, we can combine like terms

So 4a%5E2-2a-2a%2B1 factors to %282a-1%29%282a-1%29


So this also means that 4a%5E2-4a%2B1 factors to %282a-1%29%282a-1%29 (since 4a%5E2-4a%2B1 is equivalent to 4a%5E2-2a-2a%2B1)


note: %282a-1%29%282a-1%29 is equivalent to %282a-1%29%5E2 since the term 2a-1 occurs twice. So 4a%5E2-4a%2B1 also factors to %282a-1%29%5E2



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Answer:
So 4a%5E2-4a%2B1 factors to %282a-1%29%5E2