Math

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Are you allowed to do this

2log(x-1) =log(x+1)
2 (x-1)=(x+1)
x=3

Please help :)

  • Math -

    See:

    http://www.jiskha.com/display.cgi?id=1294279972

  • Math -

    Some mathteacher published a book some time ago listing all the silly solutions that students had produced.

    It actually had it this way

    2log(x-1) =log(x+1)

    (2log(x-1))/log = (log(x+1))/log , then the log/log canceled

    2(x-1) = (x+1)
    2x - 2 = x+1
    x = 3, which by sheer coincidence is the right answer.

  • Math -

    My teacher showed us this one:

    64/16
    = (6)4/1(6) [cancel the 6]
    = 4/1
    = 4

    gets the right answer, but the wrong way.

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