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Math Help - help again :)

  1. #1
    Junior Member
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    help again :)

    which number is on the number line are 3 times as far from 13 as they are from 5???
    a)1 only
    b)11 only
    c)1 and 7
    d)11 and 17

    this question i dont understand really well
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by kl050196 View Post
    which number is on the number line are 3 times as far from 13 as they are from 5???
    a)1 only
    b)11 only
    c)1 and 7
    d)11 and 17

    this question i dont understand really well
    when dealing with distance on the number line, "absolute values" is one of the first things that should come to mind.

    here we want to find all x such that

    |x - 13| = 3|x - 5|

    that is, the distance from x to 13 is 3 times the distance from x to 5

    just solve this equation for x now
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  3. #3
    MHF Contributor
    Joined
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    Talking

    Quote Originally Posted by kl050196 View Post
    which number is on the number line are 3 times as far from 13 as they are from 5???
    a)1 only
    b)11 only
    c)1 and 7
    d)11 and 17

    this question i dont understand really well
    Just plug the numbers in and see what you get!

    1:
    distance from 5: 4
    distance from 13: 12
    three times as far? yes

    11:
    distance from 5: 6
    distance from 13: 2
    three times as far? yes

    ...and so forth.
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