1. Try the following example by following the next steps 
   for getting Matlab's linprog() package to work.


objective: min 3*x1 - 2*x2 + x3


constraints:    x1 +   x2 + x3 = 1
             -3*x1 + 3*x2 - x3 = 2


conditions: x1, x2, x3 >= 0


step 0: transform the general problem to standard form.
step 1: type "help linprog" in Matlab to study the syntax 
        of Matlab's linprog script file. 
step 2: make a .m file as the input, for the above example, 
        we make sample.m script file as follows:


        c = [3 -2 1];
        A = [1 1 1 ; -3 3 -1];
        b = [1 2];


        VLB = [0; 0; 0];
        VUB = [inf; inf; inf];


        %initialization
        X0 = [0; 0; 0];


        X = lp(c, A, b, VLB, VUB, X0, 2)
 
      NOTE: You should fully make use of help in Matlab.


step3: go to Matlab, run .m file


      >> sample


2. Follow the instructions of XPRESS's   UGIGE11.PDF
   to learn how to start to work with XPRESS.
   Observe the comands:  "mp-model"  and "mp-opt"
   Make use of the help facility.   

3. Solve also the above example in XPRESS.
    
    
4. Two more examples.
   
   Murty's book: Chapter 7, p274  7.14, 7.18
   Solve these problems both with MATLAB and XPRESS.