Gauss Jacobi and Gauss Seidel
Consider the linear system of equations 
E1: 10*x1 - x2 + 2*x3        = 6 
E2:   -x1 + 11*x2 -x3 +3*x4  = 25 
E3:  2*x1 - x2 + 10*x3 -x4   = -11 
E4:       3*x2 - x3 + 8*x4   + 15 
Let's solve this problem using the Gauss Jacobi Algorithm. 
A simple script that solves this problem 
can be downloaded here .
Here are the Results for the x(i), and a tolerance of 0.001: 
 
 
The actual numbers are in the book, table 7.1
The same problem with the Gauss Seidel Algorithm:
 
Again, the actual numbers are in the book, table 7.2