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Math Help - simultaneous equations, 3 unknowns

  1. #1
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    simultaneous equations, 3 unknowns

    Hey, need some help with the methodology involved in solving simultaneous equations with three unknowns.

    I1 = I2 + I3
    8I1= 3I3
    3I1+5I2=3.4

    cheers.
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  2. #2
    Super Member craig's Avatar
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    Quote Originally Posted by clayson View Post
    Hey, need some help with the methodology involved in solving simultaneous equations with three unknowns.

    I1 = I2 + I3
    8I1= 3I3
    3I1+5I2=3.4

    cheers.
    First rearrange your second two equations to get them with respect to I1

    8I1 = 3I3, therefore I3 = \frac{8}{3}I1

    For the second one, do the same:

    3I1 + 5I2 = 3.4, 5I2 = 3.4 - 3I1, so I2 = \frac{3.4 - 3I1}{5}.

    Now put these values of I2 and I3 in to your first equation, you now have an equation in terms of just I1.

    Solve this and then put your value for I1 back into the second and third equations to find all terms.
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