clc
clear
A=[-4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0
1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 
0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0
0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 
1 0 0 0 0 0 0 -4 1 0 0 0 0 0 1 0 0 0 0 0 0 
0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0 0
0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0 0  
0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 0  
0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0 0 
0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1 0  
0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 0 1  
0 0 0 0 0 0 0 1 0 0 0 0 0 0 -4 1 0 0 0 0 0  
0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 0  
0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1 0
0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 1   
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 -4 ]
B=[0
0
0
0
0
0
-100
0
0
0
0
0
0
-100
0
0
0
0
0
0
-100]
X=A\B
for i=1:7
T=[i, X(i,1), X(i+7,1),X(i+14, 1 )]
disp(T)
end