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Math Help - Another X in exponent question.

  1. #1
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    Another X in exponent question.

    It states to to solve. The answer in the back of the book states that it's -1, 1. I just don't know where to start the questions.

    3^(2x+1) - 10*3(^x)+3=0.

    Oh by the way... how can I insert questions in proper format?

    Thanks
    Last edited by mr fantastic; September 26th 2011 at 01:33 PM. Reason: Title.
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  2. #2
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    Re: Another X in exponent question... this one seems tricky.

    Quote Originally Posted by conpark View Post
    It states to to solve. The answer in the back of the book states that it's -1, 1. I just don't know where to start the questions.
    3^(2x+1) - 10*3(^x)+3=0.
    Rewrite that as 3(3^x)^2-10(3^x)+3=0.
    Let t=3^x solve 3t^2-10t+3=0
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  3. #3
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    Re: Another X in exponent question... this one seems tricky.

    Quote Originally Posted by conpark View Post
    3^(2x+1) - 10*3(^x)+3=0.
    Oh by the way... how can I insert questions in proper format
    You can learn to post in symbols, use LaTeX tags
    [tex] 3^{2x+1} - 10\cdot 3^{x}+3=0 [/tex] gives

     3^{2x+1} - 10\cdot 3^{x}+3=0
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  4. #4
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    Re: Another X in exponent question... this one seems tricky.

    Just as a quick review, Plato is using " a^{x+y}= a^xa^y to change 3^{2x+1} to 3^{2x}3^1= 3(3^{2x}) and a^{xy}= (a^x)^y to change 3^{2x} to (3^x)^2.
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  5. #5
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    Re: Another X in exponent question... this one seems tricky.

    Thanks everyone! Wish I had found this forum earlier. It would have saved me a lot of time~
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  6. #6
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    Re: Another X in exponent question... this one seems tricky.

    HallsofIvy, is the solution simply 1 or -1 as well? I understand how to get one but the book states the solutions as -1 and 1, with the -1 listed first. Cheers
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  7. #7
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    Re: Another X in exponent question... this one seems tricky.

    Nevermind. I got it.
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