Yesterday, the best answer is: x-2x*x.  (Contributed by dnialh. Good Job!)
dnialh solved the puzzle at 20:00:23.971; length: 11
dnialh solved the puzzle at 20:00:30.778; length: 10
http solved the puzzle at 01:55:14.240; length: 11
http solved the puzzle at 01:58:30.940; length: 10