Question 746886: Hello, I would really appreciate if someone could show me how to factor the following equation using the ac method. 8x^2-22x+5. I have been trying but can not figure out how to do it. Thank you so much for your help.
Found 2 solutions by Edwin McCravy, savvyhush23: Answer by Edwin McCravy(20055) (Show Source):
You can put this solution on YOUR website!
To factor: 8x²-22x+5
Multiply the 8 by the 5 ignoring signs. Get 40
Write down all the ways to have two positive integers
which have product 40, starting with 40*1
40*1
20*2
10*4
8*5
Since the last sign in 8x²-22x+5 is +, ADD them,
and place the SUM out beside that:
40*1 40+1=41
20*2 20+2=22
10*4 10+4=14
8*5 8+5=13
Now, again ignoring signs, we find in that list of
sums the coefficient of the middle term in 8x²-22x+5
So we replace the number 22 by 20+2
8x²-22x+5
8x²-(20+2)x+5
Then we distribute to remove the parentheses:
8x²-20x-2x+5
Factor the first two terms 8x²-20x by taking out the
greatest common factor, getting 4x(2x-5)
Factor the last two terms -2x+5 by taking out the
greatest common factor, -1, getting -1(2x-5)
So we have
4x(2x-5)-1(2x-5)
Notice that there is a common factor, (2x-5)
4x(2x-5)-1(2x-5)
which we can factor out leaving the 4x and the -1 to put
in parentheses:
(2x-5)(4x-1)
To see a couple of other examples just like that using the AC
method, go here:
http://www.algebra.com/my/change_this_name32371.lesson?content_action=show_dev
Edwin
Answer by savvyhush23(50) (Show Source):
You can put this solution on YOUR website! Hello, I would really appreciate if someone could show me how to factor the following equation using the ac method. . I have been trying but can not figure out how to do it. Thank you so much for your help.
.
.
Ok, a = 8 and c = 5, their product is 40, so the closest factors that gives the sum of -22 (the middle term) are -20 and -2.
.
rewriting the -22x as -20x-2x: , divide -20 by 8 and 5 by -2,
then factor by grouping: , we have common factor ,
.
then group again, , and
simplying further divide -2 by 8, therefore, , answer!!!
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