% data for Exercise Set 2.2 
     
ex = input('Exercise number (11,12, 17,18, 21, 25-28, 31)? ');
     
if ex==11
   A = [2 4 -6;0 1 3;-3 -5 7], b = [2;5;-3]
   disp('The augmented matrix M for a system of equations corresponding to')
   disp('  Ax = b is formed by the MATLAB command:   M = [A  b]') 
elseif ex==12 
   A = [0 5 3;1 2 1;-3 -1 2], b = [-1;0;1]
   disp('The augmented matrix M for a system of equations corresponding to')
   disp('  Ax = b is formed by the MATLAB command:   M = [A  b]')  
elseif ex==17 
   u = [-5;-3;-6], A = [3 5;1 1;-2 -8], a1 = [3;1;-2], a2 = [5;1;-8] 
elseif ex==18 
   u = [8;2;3], A = [4 3 5;0 1 -1;1 2 0]
   a1 = [4;0;1], a2 = [3;1;2], a3 = [5;-1;0]  
elseif ex==21
   A = [1 3 -2 -2;0 1 -1 5;-1 -2 1 7;1 1 0 -6] 
elseif ex==23     
   A = [1 3 -4;3 2 -6;-5 -1 8], a1 = [1;3;-5], a2 = [3;2;-1], a3 = [-4;-6;8]   
elseif ex==24 
   A = [1 3 -2 -2;0 1 -1 5;-1 -2 1 7;1 1 0 -6]
   a1 = [1;0;-1;1], a2 = [3;1;-2;1], a3 = [-2;-1;1;0], a4 = [-2;5;7;-6]       
elseif ex==25 
   A = [0 0 2;0 -5 1;4 6 -3], a1 = [0;0;4], a2 = [0;-5;6], a3 =[2;1;-3]  
elseif ex==26 
   A = [3 5;1 1;-2 -8], a1 = [3;1;-2], a2 = [5;1;-8]   
elseif ex==27 
   v1 = [1;0;-1;0], v2 = [0;1;0;-1], v3 = [1;0;0;-1]   
elseif ex==28 
   v1 = [1;0;-1], v2 = [-1;3;7], v3 = [3;-2;-2] 
elseif ex==31
   u = [1;3;3], v = [-2;1;0], A = [5 1 -3;7 -2 1] 
else
   disp('No data for this exercise in Section 2.2.')  
end
