Решения СЛАУ методом Гаусса - неправильное вычисление корней

program gauss;
 
const
  n = 3;
 
var
  i, j, k, m: integer;
  a: array[1..n, 1..n] of real;
  b: array[1..n] of real;
  x: array[1..n] of real;
  e: array[1..n] of real;
  max, p, r, t, L, s, f: real;
 
begin
  {for i:=1 to n do begin
  writeln('Uravnenye:',i);
  for j:=1 to n do begin
  writeln('Vvedite A(',i,',',j,'):');
  readln(a[i,j]);
  end;
  writeln('Svobodnyi chlen: B(',i,'):');
  readln(b[i]);
  end;}
  a[1, 1] := 6; a[1, 2] := -1; a[1, 3] := -1; b[1] := 11.33;
  a[2, 1] := -1; a[2, 2] := 6; a[2, 3] := -1; b[2] := 32;
  a[3, 1] := -1; a[3, 2] := -1; a[3, 3] := 6; b[3] := 42;
  for k := 1 to n do 
  begin
    max := a[k, k];
    m := k;
    for i := k + 1 to n do
      if a[i, k] > max then begin
        max := abs(a[i, k]);
        m := i;
      end;
    for j := 1 to n do 
    begin
      p := a[k, j];
      a[k, j] := a[m, j];
      a[m, j] := p;
    end;
    r := b[k];
    b[k] := b[m];
    b[m] := r;
    {Максимальный элемент}
    
    for i := k + 1 to n do 
    begin
      L := a[i, k] / a[k, k];
      {Деление}
      for j := k to n do 
      begin
        a[i, j] := a[i, j] - a[k, j] * L;
      end;
      
      b[i] := b[i] - b[k] * L;
    end;
  end;
  {Обнуление}
  for i := 1 to n do 
  begin
    for j := 1 to n do 
    begin
      write(a[i, j]:4:2, ' ');
    end;
    write(b[i]:4:2, ' ');
    writeln;
  end;
  writeln;
  Writeln('Reshenie:');
  Writeln;
  if a[k, k] = 0 then
    if b[k] = 0 then
      Writeln('Beskonechnoe mnogo resheniy')
    else
      Writeln('Ne imeet resheniy')
  else
  begin
    for i := k downto 1 do
    begin
      s := 0;
      for j := i + 1 to k do
      begin
        s := s + a[i, j] * x[j];
      end;
      x[i] := (b[i] - s) / a[i, i];
    end;
    for i := 1 to n do
      Writeln('x[', i, ']=', x[i]:5:2);
  end;
  writeln;
  
  for i := 1 to n do 
  begin
    f := 0;
    for j := 1 to n do
      f := f + a[i, j] * x[i];
    e[i] := b[i] - f;
  end;
  
  for i := 1 to n do
    write('e[', i, ']=', e[i]:4:4, ' ');
  writeln;
  writeln;
  for i := 1 to n do 
  begin
    for j := 1 to n do 
    begin
      b[i] := e[i];
    end;
  end;
end.