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Math Help - quadratic equation problem

  1. #1
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    quadratic equation problem

    Hi I cant seem to find the roots of this x^2 - 5x + 12
    I cant do it the -b formula or standard factors?
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  2. #2
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    Quote Originally Posted by wolfhound View Post
    Hi I cant seem to find the roots of this x^2 - 5x + 12
    I cant do it the -b formula or standard factors?

    The roots of this quadratic are complex numbers since its discriminant is negative: are you working with complex numbers or only with real ones? In the latter case your answer should be "there are no real roots to the equation"

    Tonio
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    Quote Originally Posted by wolfhound View Post
    Hi I cant seem to find the roots of this x^2 - 5x + 12
    I cant do it the -b formula or standard factors?
    well the discriminant is negative which means there are at most 2 complex roots to your equation.
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  4. #4
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    Quote Originally Posted by wolfhound View Post
    Hi I cant seem to find the roots of this x^2 - 5x + 12
    I cant do it the -b formula or standard factors?
    The discriminant is negative an so you will get two complex solutions. To find these use the quadratic formula

    x = \frac{5 \pm \sqrt{5^2-4\cdot 1 \cdot 12}}{2} = \frac{5 \pm i \, \sqrt{23}}{2}

    x = \frac{5}{2} + i\, \frac{\sqrt{23}}{2}  \: \text{or} \: \frac{5}{2} - i\, \frac{\sqrt{23}}{2}
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  5. #5
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    I was not working with complex numbers but thanks for showing me the other way
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  6. #6
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    what does the i mean?
    should it be square root of - 23?
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  7. #7
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    Quote Originally Posted by wolfhound View Post
    what does the i mean?
    should it be square root of - 23?
    i = \sqrt{-1}
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