function x=gauss(A,b)
  [n,m]=size(A);
  for j=1:m-1
    for i=j+1:n;
      t=A(i,j)/A(j,j);
      A(i,:)=A(i,:)-t*A(j,:);
      b(i)=b(i)-t*b(j);
    endfor
  endfor
  x=felso(A,b);