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Re: Simple algebra problem

• To: mathgroup@smc.vnet.net
• Subject: [mg10331] Re: Simple algebra problem
• From: Allan Hayes <hay@haystack.demon.co.uk>
• Date: Thu, 8 Jan 1998 23:40:54 -0500
• References: <68q6q4$1v8@smc.vnet.net>

Eddy Wibowo wrote:

> Suppose that I have an equation of:
>         Sqrt[x+y]+ 2x + 3y == 0
>
> Now, what is the Mathematica-way to find:
>         Sqrt[x+y] = ???
>         y = ???

Eddy:
These are separate rearrangements

In[1]:=
Solve[ (Sqrt[x+y]+ 2x + 3y == 0)/.Sqrt[x+y]->s,s]/.s->Sqrt[x+y]

Out[1]=
{{Sqrt[x + y] -> -2*x - 3*y}}


In[2]:=
Solve[ (Sqrt[x+y]+ 2x + 3y == 0),y]

Out[2]=
{{y -> (1 - 12*x - Sqrt[1 + 12*x])/18},
  {y -> (1 - 12*x + Sqrt[1 + 12*x])/18}} --
Allan Hayes
Training and Consulting
Leicester, UK
hay@haystack.demon.co.uk
http://www.haystack.demon.co.uk
voice: +44 (0)116 271 4198
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