clc;
clear all;

A=[6 3 6 ; 2 3 3 ; 1 2 2 ];
[x,t]=size(a);

for i=1:m-1
    for z=2:m
        if a(i,i)==0
            t=a(j,:);a(i,:)=a(z,:);
            a(z,:)=t;
        end
    end
    for j=i+1:m;
        a(j,:)=a(j,:)-a(i,:)*(a(j,i))/(a(i,j));
    end
end

x=zeros(1,m);

for s=m:-1:1
    c=0;
    for k=2:m

        c=c+a(s,k)*x(k);
    end
    x(s)=(a(s,n)-c)/a(s,s);
end
x