Proving the Equivalence of Solving Equations and Finding Functions

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I've got a proof but I'll wait a couple days to post mine to give you guys a chance to take a crack at it.

Prove that:

For all equations E(A1, ... , An), solving for Ai is equivalent to finding the function
f(A1..A(i-1),A(i+1)...An), such that when f is substituted in E in place of Ai, E reduces to an identity (i.e. 0 = 0, 1 = 1, a^2 + b^2 = c^2, etc.)

Use whatever axioms you'd like.
 
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Seems like implicit function theorem proof.
 
Not necessary.
 
I don't think this is true. If you consider the equation x_1=x_1^2 and the function f(x_2)=0 reduces to the identity 0 = 0, but misses the solution x_1=1.
 
My wording of the problem was poor, I forgot to account for multiple independent solutions. So, here it is, better worded:
Finding a solution of Q in the equation is equivalent to finding a function f, such that when f is substituted for Q in the equation, the equation will reduce to an identity.

Both of your solutions satisfy this property, no other number satisfies this property and no other number is a solution.
 
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