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Math Help - how to solve this exponential equation?

  1. #1
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    how to solve this exponential equation?

    whats solution to (3)^2x-36(3)^x+243=0
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  2. #2
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    Re: how to solve this exponential equation?

    (3^x)^2-36(3^x)+243=0

    Substitute y=3^x if you like. Factorise.
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  3. #3
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    Re: how to solve this exponential equation?

    then you just use quadratic formula?
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  4. #4
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    Re: how to solve this exponential equation?

    That will certainly work.
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  5. #5
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    Re: how to solve this exponential equation?

    your solution set is 9, -27, but when i try testing them with original equation im not getting right answer, is there something im missing
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  6. #6
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    Re: how to solve this exponential equation?

    Quote Originally Posted by kukid13 View Post
    your solution set is 9, -27, but when i try testing them with original equation im not getting right answer, is there something im missing
    you should have found 9 and +27 for your quadratic solutions ..
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  7. #7
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    Re: how to solve this exponential equation?

    but when i try to plug those back into equation im coming up with funky answers? what am i missing
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  8. #8
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    Re: how to solve this exponential equation?

    Quote Originally Posted by kukid13 View Post
    but when i try to plug those back into equation im coming up with funky answers? what am i missing
    3^x = 9

    x = 2

    you do the other solution ...
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