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Thread: Indices Problem!

  1. #1
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    Indices Problem!

    using indices only, and the substitution y=2^x , solve the equation:

    2^2x - 6.2^x + 8 = 0
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  2. #2
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    Okay, could you perform the substitution?
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  3. #3
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    Maybe it will help if you rewrite your equation as

    $\displaystyle \displaystyle \left(2^x\right)^2 - 6\cdot 2^x + 8 = 0$...
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  4. #4
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    im lost as to where the substitution goes? and the question is written exactly as shown out of previous exam paper.
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  5. #5
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    Look at Prove It's response. See those "$\displaystyle 2^x$"s? Replace those with y.
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  6. #6
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    Quote Originally Posted by HallsofIvy View Post
    Look at Prove It's response. See those "$\displaystyle 2^x$"s? Replace those with y.
    And once you have done that, solve for $\displaystyle \displaystyle y$, the solution of which you can use to solve for $\displaystyle \displaystyle x$.
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