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Math Help - Algebra factoring equations

  1. #1
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    Algebra factoring equations

    2x^2+8x+8=0

    25e^2+90e+81=0

    The answers should be in x=? x=?
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  2. #2
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    2x^2+8x+8 = 0

    2(x^2+4x+4) = 0

    x^2+4x+4 factors into (x+2)(x+2)

    2(x+2)^2= 0

    X = -2

    I don't know about the second one.
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  3. #3
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    Quote Originally Posted by Belanova View Post
    2x^2+8x+8=0

    25e^2+90e+81=0

    The answers should be in x=? x=?
    In general, a^2 + 2ab + b^2 = (a + b)^2. So:

    2(x^2 + 4x + 4) = 0 => 2(x + 2)^2 = 0 .......

    (5e + 9)^2 = 0 ........
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  4. #4
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    Thanks very much. What about these?
    48q^2+168q+147=0
    147r^2+126r+27=0
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  5. #5
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    Quote Originally Posted by Belanova View Post
    Thanks very much. What about these?

    48q^2+168q+147=0 Mr F says: 3(4q + 7)^2 = 0

    147r^2+126r+27=0 Mr F says: Take out a common factor (hint: 3) and write as a perfect square. Same as the others.
    ..
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  6. #6
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    Wow, that makes those problems incredibly simple. I was never taught that, thanks.

    Quote Originally Posted by mr fantastic View Post
    In general, a^2 + 2ab + b^2 = (a + b)^2. So:

    2(x^2 + 4x + 4) = 0 => 2(x + 2)^2 = 0 .......

    (5e + 9)^2 = 0 ........
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  7. #7
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    Quote Originally Posted by coach2uf View Post
    Wow, that makes those problems incredibly simple. I was never taught that, thanks.
    It only works for a quadratic trinomial that's a perfect square. That is, something that has the form a^2 \pm 2ab + b^2.
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