Free Download Polymath 6.1 (free version)

Polymath Educational is a software tool that is designed to help users apply numerical analysis methods and solve problems in a variety of fields, including engineering, mathematics, and science. The software includes a variety of programs that allow users to perform interactive problem solving on their personal computers, and it displays results graphically for easy understanding and integration into papers and reports. Polymath Educational is intended for use by professionals and students who need to solve problems and may be particularly useful for engineers, mathematicians, and scientists.

You can download a free version of it with following link

https://polymath.software.informer.com/download/

It is for following areas

• Linear Equations - up to 264 simultaneous equations
• Nonlinear Equations - up to 300 simultaneous nonlinear and 300 additional explicit algebraic equations
• Differential Equations - up to 300 simultaneous ordinary differential and 300 additional explicit algebraic equations
• Data analysis and Regression - up to 200 variables with up to 1000 data points for each, with capabilities for linear, multiple linear, and nonlinear regressions with extensive statistics plus polynomial and spline fitting with interpolation and graphing capabilities