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Math Help - inequality (am i correct ?)

  1. #1
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    inequality (am i correct ?)

    Hi ! I think I am doing the right thing here.

    Given:
    Solve for the solution set:

    | 7x - 1 | - 6 < 2

    My solution:
    -1 < x < (9/7)

    My sleepy instructor says the correct solution is

    -1 < x < - (9/7)

    I would just like to verify. Thank you !!!
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  2. #2
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    \displaystyle |7x - 1| - 6 < 2

    \displaystyle |7x - 1| < 8

    \displaystyle -8 < 7x - 1 < 8

    \displaystyle -7 < 7x < 9

    \displaystyle -1 < x < \frac{9}{7}.


    Your answer is correct.
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  3. #3
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    I would hope that you instructor, no matter how sleepy, would recognize that "-1< -(9/7)" itself is not true!
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