alintugaskelompok.m

a = [4 2 1 1; 1 -1 3 20; 2 1 1 3];

[m,n]=size(a);
for j=1:m-1
    for z=2:m
        if a(j,j)==0
            t=a(j,:);a(j,:)=a(z,:);
            a(z,:)=t;
        end
    end
    for i=j+1:m
        a(i,:)=a(i,:)-a(j,:)*(a(i,j)/a(j,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
disp('Cara Gauss:');
a

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

for j=m:-1:2
    for i=j-1:-1:1
        a(i,:)=a(i,:)-a(j,:)*(a(i,j)/a(j,j));
    end
end

for s=1:m
    a(s,:)=a(s,:)/a(s,s);
    x(s)=a(s,n);
end
disp('Cara Gauss jordan:');
a

x = a(3,4)
y = a(2,4)
z = a(1,4)