A = [ 2 4 -2 ; 4 9 -3 ; -2 -3 7]

b = [ 2 8 10]'

Aug = [A b]

for j=2:3,
  for i=j:3,
    Aug(i,:) = Aug(i,:) - Aug(j-1,:)*Aug(i,j-1)/Aug(j-1,j-1)
  end
end