simultaneous equations

Discussion in 'Math' started by amilton542, Feb 22, 2011.

  1. amilton542

    Thread Starter Active Member

    Nov 13, 2010
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    i dont have great difficulty in rearranging simultaneous equations with an x and y value equals a number but when a third value is put in things confuse me : im trying to rearrange this formula

    y = 8 - 2x
    x + y + 7 = 0

    ive rearranged the top one to y + 2x = 8

    the second one i dont no what to do with the zero ? my attempt is x + y = 0 - 7
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    Quite right. Can you solve the system now?
     
  3. amilton542

    Thread Starter Active Member

    Nov 13, 2010
    494
    64
    maths guru is that a yes your answer is right ( keep all cons together) then i can solve the "system"
     
  4. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    Yes, I said that your assumption about putting the '7' on the right hand expression was correct. Your new system should be:

    \left\  \begin{array}{l} y+2x=8 \\ x+y=-7\\<br />
\end{array} \right}

    Can you handle that system? Do you need any more help?
     
    Last edited: Feb 22, 2011
  5. amilton542

    Thread Starter Active Member

    Nov 13, 2010
    494
    64
    just what i was looking for ;)
     
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