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Math Help - 6x+3=2x-7...how to find x?

  1. #1
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    6x+3=2x-7...how to find x?

    How can you find x in this equation? and if you can please answer this problem--and explain why.

    Two hikers left at 9:00. The other hiked south with a speed of 4km/h while the other hiked north at 3km/h.How long can they stay connected if their walkie-talkies've got a max. range of 10km? (Sorry for the bad english, the problem was written in french).
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  2. #2
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    Hello Julian.Ignacio!

    Quote Originally Posted by Julian.Ignacio View Post
    How can you find x in this equation? and if you can please answer this problem--and explain why.

    6x+3=2x-7

    add +7 to both sides:

    6x + 3 +7 = 2x - 7 + 7

    6x + 10 = 2x + 0

    add -6x on both sides:

    6x +10 - 6x = 2x - 6x

    10 = -4x

    divide by -4

    - (10/4) = x

    -10/4 is equal to -5/2


    Quote Originally Posted by Julian.Ignacio View Post
    Two hikers left at 9:00. The other hiked south with a speed of 4km/h while the other hiked north at 3km/h.How long can they stay connected if their walkie-talkies've got a max. range of 10km? (Sorry for the bad english, the problem was written in french).
    I give you a hint: because one hiker goes north 3km/h, the other goes south 4km/h, it is like there is only one hiker traveling into one direction with (3+4)km/h = 7km/h.
    Then you want to know how long it takes to reach the 10km mark.

    So you need to solve

    7 (km/hours) * x (hours) = 10 (km)


    Yours
    Rapha
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  3. #3
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    Talking

    Quote Originally Posted by Julian.Ignacio View Post
    How can you find x in this equation? and if you can please...explain why.
    To learn the "why" and "how", try here.
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  4. #4
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    @Stapel: Haha thanks! I chose math-bilingual so my math is in french; I really needed a theory in english!!! THANK YOU!!!!!!!!!
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