% data for Exercise Set 1.2 
   
ex = input('Exercise number (7-21)? ');
    
if ex==7    
   M = [1 0 2 5;2 0 3 6]    
elseif ex==8    
   M = [1 -3 0 -5;-3 7 0 9]     
elseif ex==9    
   M = [0 3 6 9;-1 1 -2 -1]   
elseif ex==10
   M = [1 3 -3 7;3 9 -4 1] 
elseif ex==11    
   M = [1 4 2 3;-2 -8 -1 9] 
elseif ex==12
   M = [1 3 6 9;-1 1 -2 -1]         
elseif ex==13
   M = [2 -4 3;-6 12 -9;4 -8 6] 
elseif ex==14
   M = [1 2 4;-2 -3 -5;2 1 -1] 
elseif ex==15
   M = [1 2 -7;-1 -1 1;2 1 5] 
elseif ex==16  
   M = [1 0 0 8 -3;0 1 0 4 -6;0 0 1 -7 5;0 0 0 0 0]         
elseif ex==17
   M = [1 0 -9 0 4;0 1 3 0 -1;0 0 0 1 -7;0 0 0 0 1] 
elseif ex==18    
   M = [1 5 0 0 3;0 0 1 0 -2;0 0 0 1 6;0 0 0 0 1] 
elseif ex==19
   M = [1 -2 0 0 7 -3;0 1 0 0 -3 1;0 0 0 1 5 -4;0 0 0 0 0 0] 
elseif ex==20
   M = [1 0 -5 0 -8 3;0 1 4 -1 0 6;0 0 0 0 1 0;0 0 0 0 0 0] 
elseif ex==21
   M = [1 0 -2 0 0 0;0 1 6 -3 -2 7;0 0 0 1 0 -5;0 0 0 0 1 0] 
else
   disp('No data for this exercise in Section 1.2.')  
end
