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Math Help - absolute values are SCArY!!!

  1. #1
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    Exclamation absolute values are SCArY!!!

    i understand that an absolute value is the distance on a number line from zero, and that abs(y)=8 would be 8, -8, but when it gets to like abs(c/4)=9, i know you have to make two equations, c/4=9 and c/4=-9, because my sheet says so, but why? i don't understand why the 9 is affected when it is not in the absolute value bars.......
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  2. #2
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    By definition |a|\leq b \Rightarrow -b \leq a \leq b

    Why?

    Look at the function y = |x|
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  3. #3
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    [quote=pickslides;355065]By definition |a|\leq b \Rightarrow -b \leq a \leq b

    i was never taught absolute value by that equation before... so if abs(w-8)=7, then would i set up the equation to be w-8=16 and w-8=-16 and then solve?
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    Quote Originally Posted by jazzyredsox5 View Post
    so if abs(w-8)=7, then would i set up the equation to be w-8=16 and w-8=-16 and then solve?

    So what are you asking? I am confused how 7 can be equal to 16?

    I'm guessing you are saying |w-8|\leq 7 \Rightarrow -7 \leq w-8 \leq 7

    Therefore solve both

     -7 \leq w-8

     1 \leq w

     w \geq 1

    and

    w-8 \leq 7

    w \leq 15
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