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Math Help - Solving for x help

  1. #1
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    Solving for x help

    Can someone please help me out with this.

    3^5+2x = 1/9x

    I'm not looking just for the answer (since i have it) but i want to understand it.

    Here's my rough work.


    3^5+2x = 1/ 9^x

    = 3^5+2x = 1 / (3^2)^x

    5+2x = 2x

    0x = -5


    ... I know i made a mistake somewhere there... the actual answer is x = -5/4 but I have no idea how you get it since the 2 is not negative...

    Thanks.
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  2. #2
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    Hello, agent2421!

    You left out a step . . . and that's where your mistake occured.


    3^{5+2x} \:=\: \dfrac{1}{9^x }

    3^{5+2x} \:=\: \dfrac{1}{9^x}

    3^{5+2x} \;=\;\dfrac{1}{(3^2)^x}

    3^{5+2x} \;=\;\dfrac{1}{3^{2x}}

    3^{5+2x} \:=\: 3^{-2x} .
    Here!

    Got it?

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  3. #3
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    Quote Originally Posted by agent2421 View Post
    3^5+2x = 1/9x
    Very badly posted; should be: 3^(5 + 2x) = 1 / 9^x
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