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RE: Is mathematica able to transform formula


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



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