clc;
clear all;
close all;
X=[1,1,1,0;2,2,1,-1;0,3,1,2;1,2,2,1];
Y=[4;6;-1;4];
Z=[X,Y];

while ismember(0,diag(X))
    for i=1:size(X,1)
        if X(i,i)==0
            for j=1:size(X,1)
                if X(j,j)~=0
                  Z([i,j],:)=Z([j,i],:);
                  X([i,j],:)=X([j,i],:);
                end;
            end;
        end;
    end;
end;




for i=1:size(Z,1)
if Z(i,i)==0
   Z(i,:)=Z(i,:)+Z(i+1,:);
end;
Z(i,:)=Z(i,:)./Z(i,i);
    for j=1:size(Z,1)
        if i ~= j
            Z(j,:)=Z(j,:)-(Z(i,:).* Z(j,i));

        end;
    end;
end;

Z
wynik=Z(:,size(Z,2))