simultaneous equations - eliminating variables and solving

*To*: mathgroup at smc.vnet.net*Subject*: [mg100210] simultaneous equations - eliminating variables and solving*From*: nninja <not.a.ninja25 at gmail.com>*Date*: Thu, 28 May 2009 04:28:39 -0400 (EDT)

Hi, I am a postgrad student and completely new to mathematica, I am just starting to realise the possibilities. I am trying to do a chemical speciation calculation. I have a set of simultaneous equations which represents the equilibria, mass balance, and charge balance in the system. I want to eliminate some of the variables, and then be able to solve for the remaining ones. My system of equations looks like this: a=b+c+d e=f+g+c+2d h=c/(bg) i=d/(cg) hi=d/(bg^2) j=mg/f k=lm n+m+b+c=g+l This is what my formula looks like sofar. Solve[{a == b + c + d, e == f + g + c + 2 d, h == c/(b*g), i == d/(c*g), h*i == d/(b*g^2), j == m*g/f, k == l*m, n + m + b + c == g + l}, {g}] Basically, I can solve for the variable I want, but I am having trouble eliminating the ones I don't want (ie. I am getting an answer that is in terms of the wrong variables) I have been in the help files for ages, and don't really understand how to do this. I would really appreciate some pointers!! Thanks