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Math Help - Absolute Value Equations

  1. #1
    TNB
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    Unhappy Absolute Value Equations

    Need help w/ an absolute value problem where a no. is placed outside the equation within the absolute value signs-what should I do first?
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by TNB View Post
    Need help w/ an absolute value problem where a no. is placed outside the equation within the absolute value signs-what should I do first?
    since you chose to be vague, the most i can tell you is that

    |x| = \sqrt{x^2} = \left \{ \begin{array}{lr} x & \mbox{ if } x \ge 0 \\ & \\ -x & \mbox{ if } x < 0 \end{array} \right.

    so you need to split your equation in two to account for the possible change in sign of what's in absolute values.

    example. |3x - 1| = 2

    \Rightarrow 3x - 1 = 2 \mbox{ or } -(3x - 1) = 2

    and continue
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  3. #3
    TNB
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    It's like your final ex, save there's a number attached to the back end.



    somthing like this...... 7

    Sorry about the lack of detail. Just trying to speed things up.. Typing wise, anyhow.
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  4. #4
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by TNB View Post
    It's like your final ex, save there's a number attached to the back end.



    somthing like this...... 7

    Sorry about the lack of detail. Just trying to speed things up.. Typing wise, anyhow.
    well, that's no problem. divide both sides by 7 first, you get

    |3x - 1| = 2/7

    then it is pretty much exactly like my example
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  5. #5
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    Absolute value

    In that case, do NOT multiply the 7 with the expression 3x - 1. That'll change the absolute value! Instead, divide 7 on both sides, and then proceed.

    |3x - 1| = 2/7

    Now proceed...

    I hope that helps.

    ILoveMaths07.

    P.S. THIS IS MY FIRST POST!!!
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  6. #6
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ILoveMaths07 View Post
    P.S. THIS IS MY FIRST POST!!!
    congrats!
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  7. #7
    TNB
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    Thank you Jhevon.

    Much thanks. Couldn't really remember whether to subtract or divide.....
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  8. #8
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    You can't subtract because it's  7 * |3x - 1| . You must divide the 7 on both sides.
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