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Homework Help: Simulatenous Equations

  1. Dec 4, 2011 #1
    1. The problem statement, all variables and given/known data

    I am asked to find the two variables in a simulatenous equation. Now I have found one variable but unsure on how to find the other (P2).

    2. Relevant equations
    [itex] 5p1 - 4p2 = 49[/itex]
    [itex] 3p1 + 2p2 = 3[/itex]

    3. The attempt at a solution

    [itex] 5p1 - 4p2 = 49[/itex] (Multiply by 2)
    [itex] 3p1 + 2p2 = 3[/itex] (Multiply by 4)

    [itex] 10p1 = 98[/itex]
    [itex] 12p1=12 [/itex]

    Add the two together

    [itex] 22p1=110[/itex]
    [itex] p1=5[/itex] (110 divided by 22)
     
  2. jcsd
  3. Dec 4, 2011 #2
    plug the value of p1 back into either equation to find p2. Actually, put it back in to both to make sure you get the same answer for p2 each time.
     
  4. Dec 4, 2011 #3
    Thank you! I couldn't quite remember what to do.

    So what I got was
    [itex](5(5) - 49)/4 = -6 [/itex]
    [itex](5(3) - 3)/2 = -6 [/itex]

    So [itex] P2 = -6 [/itex] Thanks!!!
     
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