SimSolve is a Home & Education software developed by Living Logic Pty Ltd. After our trial and test, the software is proved to be official, secure and free. Here is the official description for SimSolve:
Brothersoft Editor: A fast, general purpose and FREE simultaneous Equation solver. Just specify the number of variables, enter the coefficients, and press solve. Reports the numerical solution if only one exists, describes the constraints if infinite solutions exist, and tells you it's impossible if no solution exists. The "show workings" mode explains how the program came to its conclusions. you can free download SimSolve 2.1 now.