RE: Is mathematica able to transform formula

*To*: mathgroup at smc.vnet.net*Subject*: [mg71879] RE: [mg71864] Is mathematica able to transform formula*From*: "David Park" <djmp at earthlink.net>*Date*: Sat, 2 Dec 2006 05:10:45 -0500 (EST)

pujo, Do you mean that you want to do it in steps, like one might do it by hand? Then you could use the following. eqn1 = f == a b + 5; eqn2 = c == a b; Inner[Subtract, eqn1, eqn2, Equal] # + c & /@ % giving -c + f == 5 f == 5 + c We first subtracted the two equations, and then used a pure function to add c to both sides. If you wanted a more complicated combination of the two equations, say 2 times the first equation minus three times the second equation, then you could use a pure function in the Inner command rather than Subtract. 2 #1 - 3 #2&. You could also do it using Solve Equal @@ Part[Solve[{eqn1, eqn2}, f, a], 1, 1] f == 5 + c David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: ajikoe at gmail.com [mailto:ajikoe at gmail.com] Hello, I have a question: if I have a symbolic expression: f = a * b + 5 c = a * b Can Mathematica builds f = c + 5 for me ? Sincerely Yours, pujo