       Re: Problem with replacement rules

• To: mathgroup at smc.vnet.net
• Subject: [mg91882] Re: Problem with replacement rules
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Thu, 11 Sep 2008 06:17:36 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <ga82r6\$re7\$1@smc.vnet.net>

```Simula wrote:

> Hello, I have a very simple question but I didn't find an answer in mathematica help.
> I use Solve[expression(x,y),x]. Then, x is obtained as a one-to-one function of y. I want to define the function x(y) using the output of Solve. How should I do?

In:= (* Solve the expression for x and save the result in sol *)
sol = Solve[a * x + y == 7, x]

(* Define x as a function of y *)
x[y_] = x /. sol[]

(* Use the function *)
x

Out= {{x -> (7 - y)/a}}

Out= (7 - y)/a

Out= -(3/a)

Regards,
-- Jean-Marc

```

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