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Math Help - can you help me with this?

  1. #1
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    can you help me with this?

    am I in the right track??

    9\ge\frac{8-x}{4}>0

    9-2\ge\frac{-x}{4}>-2

    7(4)\ge-x>2(4)

    28\ge-x>8

    i am confused when changing -x to x

    28\le x<-8

    is this correct??

    another example
    -x>-8
    x<-8

    thanks I'm confused
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  2. #2
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     <br />
0 < \frac{8-x}{4} \leq 9<br />

    multiply every term by 4 ...

     <br />
0 < 8-x \leq 36<br />

    subtract 8 ...

     <br />
-8 < -x \leq 28<br />

    one inequality at a time ...

    -8 < -x ... 8 > x ... x < 8

    -x \leq 28 ... x \geq -28

    final solution ...

     <br />
-28 \leq x < 8<br />
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  3. #3
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    Quote Originally Posted by skeeter View Post
     <br />
0 < \frac{8-x}{4} \leq 9<br />

    multiply every term by 4 ...

     <br />
0 < 8-x \leq 36<br />

    subtract 8 ...

     <br />
-8 < -x \leq 28<br />

    one inequality at a time ...

    -8 < -x ... 8 > x ... x < 8

    -x \leq 28 ... x \geq -28

    final solution ...

     <br />
-28 \leq x < 8<br />

    so this means i will change the signs of both terms?/
    like this -x>8 then x<-8
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  4. #4
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    Quote Originally Posted by princess_21 View Post
    so this means i will change the signs of both terms?/
    like this -x>8 then x<-8
    yes ... what you have done is multiply both sides of the inequality by -1 ... you also must change the direction of the sign anytime you multiply or divide by a negative value.

    for example ...

    5 > 4

    multiply both sides by -1 ...

    -5 < -4
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