Solving NonLinear Equations

["Bert Jacobs" <b.jacobs@pandora.be>]

Hello,

I was wondering if S-Plus could help me solve the equations in the example
below. Normally I use the function solve to get results for a linear
equation system but now I have to deal with nonlineair equations.

3,059,738   = 0.62653*x + c                                     
783,717     = 0.53653*y + d                                     
y             = 0.320*x                                                 
0.256138456     = ((5.52868E-08*x*c) + d - (2.04766E-07*d*x))/c

Anybody an idea?  Is this possible in S-Plus? 
Normally the equation above should give a unique solution, can I check this
in a way?

Thx a lot for helping me out,
Bert