Solving linear equations systems with > 9 variables accurately?

[Marcio]

(06-08-2015 11:51 AM)Bernd Grubert Wrote:  Hello Dieter,
There are even more free open source alternatives:
Numeric calculations: OCTAVE (a MATLAB clone), Python with numpy and scipy modules.
Symbolic/numeric calculations: MAXIMA.

Regards
Bernd

Last time I used Octave was 3 years ago. It seems things improved considerably since then. There was not even a stable version for windows. I had to install cygwin (Unix-like environment and command-line interface for windows) to get it run to my satisfaction.
Octave now has a beautiful UI. Congrats to the development team!!