Re: Setting up equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg66027] Re: Setting up equations*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Thu, 27 Apr 2006 02:26:26 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <e2nd3i$33m$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Yaroslav Bulatov wrote: > I'm trying to do things of the form > Solve[5 x + 6 y + 7 z == a x + b y + c z, {a, b, c}] > > But since x,y,z are variables, what I really mean is > Solve[5==a && 6==b && 7==c], so I need to convert to this form > > If I only have one variable, the following does what I need > > LogicalExpand[a*x + b*x^2 + O[x]^3 == 2*x + 3*x^2 + O[x]^3] > > But what to do if I have several variables? > Hi Yaroslav, Try *Reduce* rather than *Solve* and use *ForAll* to put a condition on x, y, and z. In[1]:= Reduce[ForAll[{x, y, z}, 5*x + 6*y + 7*z == a*x + b*y + c*z], {a, b, c}] Out[1]= a == 5 && b == 6 && c == 7 Best regards, Jean-Marc