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Math Help - quick easy question im sure

  1. #1
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    quick easy question im sure

    can someone explain to me how -y=-|x|+2 turns into y=|x|-2
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  2. #2
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    Dear wonderd,

    Multiply the whole equation by -1.
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  3. #3
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    i dont understand, i do understand that to get the y by itself you divide by -1 but what are you suspose to do to the other side of the equal sign?
    can someone explain how to divid -1 by -|x|+2 properly?
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  4. #4
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    Quote Originally Posted by wonderd View Post
    i dont understand, i do understand that to get the y by itself you divide by -1 but what are you suspose to do to the other side of the equal sign?
    can someone explain how to divid -1 by -|x|+2 properly?
    You divide each of the terms by -1:

    \frac{-|x|}{-1} = |x|

    \frac{2}{-1} = -2

    Thus, you end up with |x|-2.
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  5. #5
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    thank you
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  6. #6
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    Or, as sudharaka said, multiply both sides of the equation by -1:
    (-1)(-y)= (-1)(-|x|+ 2). The left is, of course, y and on the right you have (-1)(-|x|)+ (-1)(2)= |x|- 2.
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  7. #7
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    Quote Originally Posted by wonderd View Post
    can someone explain to me how -y=-|x|+2 turns into y=|x|-2
    Hi wonderd,

    you may add y to both sides

    -y=-|x|+2

    y-y=y-|x|+2

    0=y-|x|+2

    add |x| to both sides

    |x|=y+|x|-|x|+2

    |x|=y+2

    subtract 2 from both sides

    |x|-2=y+2-2,\ |x|-2=y

    It's much quicker to multiply both sides by -1
    or divide both sides by -1, but it helps to know how to juggle.
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