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  • Oct 5, 2010, 03:13 PM
    LynnM
    Exponential Equation
    Can anyone help me with this question:

    ( [(9^{2x-1}) (3^{3x})^2] / [(27^{x+2})^4] ) = 81^3

    I know that x=-19 but I keep getting -1.5 and 8. Step by step would be really appreciated. Thank you.
  • Oct 6, 2010, 01:59 AM
    Unknown008



    Okay, put everything to base 3.



    Now, work out the powers:



    Now, you know that and

    Apply this:



    Now, simplify:



    Equate the powers:



    This gives you:

  • Oct 6, 2010, 07:03 AM
    LynnM
    Thanks once again! I now see where I was going wrong. After I worked out the powers, instead of adding the top powers, I was trying to multiply them. (Actually, I think I did try to add them at one point but still ended up with the wrong answer!) Oye! Lol!

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