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Math Help - numbers in different bases

  1. #1
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    numbers in different bases

    Hi Im studying for finals and Ive been looking up the old exams and one reoccuring question that i cant quite get my head around is for example they give u a number in a base and then give a number thats equal to it in another base and the question is to find the unknown base

    eg. (456) in base b = (2201) in base 7
    find b.
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  2. #2
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    Why is this not just a test of your knowledge of the base positional system?

    456 (b) = 2201 (7)

    so

    4*b*b + 5*b + 6 = 2*7*7*7 + 2*7*7 + 0*7 + 1

    Solve for 'b'. In this case, it's only quadratic so you should be able to solve it. Of course, since we need a nice whole number, you should be able to factor it. Further, since you just made this one up, or it's a really odd example, you'll need to find some other way to solve the quadratic.
    Last edited by TKHunny; December 12th 2009 at 08:20 PM.
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  3. #3
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    yah when i tried to solve it u get imaginary roots which is really weird since its a question off last years exam. Im not sure what else to do.
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  4. #4
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    No, they are Irrational, but Real. That's a bit unusual.

    Not every question is designed perfectly. Not every answer is neat and clean.
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