After the number of variables has been selected a click on Apply will open a formular to enter the matrix/coefficients. By clicking Solve the computation starts and the results are presented in following order: 1. The determinant of the matrix; 2. The numbers, which solve the system; 3. The errors, which the solution produces for each equation (left side of the equation minus right side). If 'Determinant only' is checked, one will be given the possibility to compute the determinant of a square matrix.