1. Joined
    21 Oct '04
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    17038
    14 May '06 23:273 edits
    I know this is not the place to ask math questions, but since Im doing an online math class, Its hard for me to ask a real person.

    In my Math textbook, Im having a hard time understanding this problem, I know its something simple, I just cant figure out what. The fact that Im dum at math isnt helping any.

    Simplify: -2(x-5)+ 4(2x + 2)


    This is how the book says to simplify.
    -2(x-5)+ 4(2x + 2) = -2*x + (-2)(-5) + 4*2x + 4/2
    = -2x + 10 + 8x +8
    = 6x + 18


    This is how it seems to me it should go, which gives it a totaly different answer.
    -2(x-5)+ 4(2x + 2) = -2*x -(-2)(-5) + 4*2x + 4/2
    = -2x - 10 + 8x +8
    = -2x + (-10) + 8x +8
    = 6x + (-2) or = 6x - 2

    So what am I doing wrong? Why are they changing the minus sign to a plus sign when they are caculating, for no reason at all?

    * = mutiply
  2. Earth Prime
    Joined
    16 Mar '05
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    21936
    14 May '06 23:38
    Originally posted by flyUnity
    This is how it seems to me it should go, which gives it a totaly different answer.
    -2(x-5)+ 4(2x + 2) = -2*x -(-2)(-5) + 4*2x + 4/2
    = -2x - 10 + 8x +8
    = -2x + (-10) + 8x +8
    = 6x + (-2) or = 6x - 2

    So what am I doing wrong? Why are they changing the minus sign to a plus sign when they are caculating, for no reason at all?

    * = mutiply
    your problem is in the first distribution. The -2 needs to go to the x, which you did right, but also to the -5, and (-2)*(-5) is (+10).
  3. Joined
    21 Oct '04
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    17038
    14 May '06 23:43
    Originally posted by Coconut
    your problem is in the first distribution. The -2 needs to go to the x, which you did right, but also to the -5, and (-2)*(-5) is (+10).
    Ok, I got it now, I dont know what I was thinking. Thanks 🙂
  4. Standard memberXanthosNZ
    Cancerous Bus Crash
    p^2.sin(phi)
    Joined
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    16 May '06 12:27
    Originally posted by flyUnity
    Ok, I got it now, I dont know what I was thinking. Thanks 🙂
    Hope you are never plotting a course for a plane I'm on.
  5. Joined
    21 Oct '04
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    17038
    16 May '06 21:07
    Originally posted by XanthosNZ
    Hope you are never plotting a course for a plane I'm on.
    Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. 😛
  6. Joined
    24 Mar '06
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    2083
    20 May '06 17:59
    Originally posted by flyUnity
    Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. 😛
    i hope the buttons are not plus or minus buttons lols

    thanks for the laugh
  7. Account suspended
    Joined
    22 May '06
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    2855
    23 May '06 18:30
    Originally posted by flyUnity
    Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. 😛
    press a wrong button, how do you know you're not flying off into oblivion?
  8. Joined
    21 Oct '04
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    17038
    24 May '06 01:48
    Hey, Im not that dumb. Flying is easier then driving a car.
  9. Back Home.
    Joined
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    26 May '06 09:041 edit
  10. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
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    52724
    30 May '06 00:32
    Originally posted by flyUnity
    Hey, Im not that dumb. Flying is easier then driving a car.
    Especially if you are in a plane.
  11. Standard memberBowmann
    Non-Subscriber
    RHP IQ
    Joined
    17 Mar '05
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    1345
    30 May '06 01:46
    I learnt that a minus times a minus is a plus when I was four months old.
  12. B is for bye bye
    Joined
    09 Apr '06
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    30 May '06 02:07
    Originally posted by Bowmann
    I learnt that a minus times a minus is a plus when I was four months old.
    Slow learner.
  13. SubscriberAThousandYoung
    All My Soldiers...
    tinyurl.com/y9ls7wbl
    Joined
    23 Aug '04
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    24791
    30 May '06 02:17
    Originally posted by flyUnity
    Hey, Im not that dumb. Flying is easier then driving a car.
    Umm...are you telling us it's ok that you're a pilot even though driving is too difficult for you?
  14. Standard memberBowmann
    Non-Subscriber
    RHP IQ
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    30 May '06 02:34
    Originally posted by Gastel
    Slow learner.
    I was busy studying philosophy.
  15. Joined
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    6710
    30 May '06 03:56
    Originally posted by Bowmann
    I was busy studying philosophy.
    "studying"? "philosophy"? oxymoron?
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