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Homework Help: This problem. 2^x + 2^-x = 3

  1. Jul 30, 2011 #1
    3. The attempt at a solution

    2^x + 2^-x = 3

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

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

    (4^((x^2)) + 1) = 6^ x
     
  2. jcsd
  3. Jul 30, 2011 #2

    HallsofIvy

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    No, 2(3^x) is not the same 6^x.
     
  4. Jul 30, 2011 #3

    gb7nash

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    Multiply both sides by 2x instead.
     
  5. Jul 30, 2011 #4
    My bad. I forgot that they must have the same base to multiply them. Also, If you're referring to the last step, I did multiply both sides by 2^x. I'm stuck at that point though.
     
  6. Jul 30, 2011 #5
    let u = 2^x
    solve the quadratic
    after solve for u solve for x
     
  7. Jul 30, 2011 #6
    Thanks that helped a lot. Thanks everyone for the quick replies
     
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