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25 January, 12:52

Using the AC method Ax^2 + Bx+C

How do I solve this problem? and check the answer back into equation? Mark as brainlest on my list!

25x^2 - 20x + 4

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Answers (2)
  1. 25 January, 13:06
    0
    25=5*5=1*25

    4=2*2=1*4

    Factor to get sum of-20

    (5x-2) (5x-2)

    solve 5x-2=0=>x=2/5 is root of multiplicity 2 for both functions.
  2. 25 January, 13:37
    0
    So

    find ac

    list all products that equal ac

    find the ones that add to b

    rewrite

    factor

    undistribute

    so

    25x^2-20x+4

    ac=4*25=100

    what 2 numbers, when multipied together, results in 100 but adds to - 20?, I did this in previous quesiton, the answer is - 10 and - 10

    25x^2-10x-10x+4

    (25x^2-10x) + (-10x+4)

    (5x) (5x-2) + (-2) (5x-2)

    factor out (5x-2)

    (5x-2) (5x-2)

    well, there is no equal sign, but we will assume it equals 0

    (5x-2) ^2=0

    5x-2=0

    5x=2

    x=2/5
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