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Math Help - exactly equal

  1. #1
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    exactly equal

    Hi everyone

    I am new here looking for a bit of help. Hopefully in the future I will be able to offer others some help.

    I have been brushing up on my maths skills as I am starting a Home study maths degree. I have come accross the following question, and although I have trawled through many books, I can get nowhere with it.

    X^2-aX+144=(x-b)^2

    Find a and b.

    Looks like something to do with a quadratic to me but I am totally stuck on how to get to the answer.

    Any help would be greatly appreciated. Thanks.

    James
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  2. #2
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    Quote Originally Posted by futureprof View Post
    Hi everyone

    I am new here looking for a bit of help. Hopefully in the future I will be able to offer others some help.

    I have been brushing up on my maths skills as I am starting a Home study maths degree. I have come accross the following question, and although I have trawled through many books, I can get nowhere with it.

    X^2-aX+144=(x-b)^2

    Find a and b.

    Looks like something to do with a quadratic to me but I am totally stuck on how to get to the answer.

    Any help would be greatly appreciated. Thanks.

    James
    (x - b)^2 = (x - b) (x - b) = x^2 - 2bx + b^2.

    Compare this with x^2 - ax + 144:

    -2b = -a \Rightarrow 2b = a .... (1)

    b^2 = 144 \Rightarrow b = \pm 12 .... (2)

    b = 12: a = 24.

    b = -12: a = -24.
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  3. #3
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    Thanks for that.

    So easy now I see it writen out.
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