c = [ -2 -1 0 0 0 ]' ;
b = [ 1 0.75 10 ]' ;
A = [ 1   1   1   0   0  
      1   0   0   1   0  
      8  20   0   0   1 ];
bix = [3 4 5];
zcheat=-1.7;
xcheat = [0.75 0.2 0.05 0 0]';

