4 x 2 12 x 5 0 July 8, 2019 16 32 64 128 X 4 2 x 12 x 5 x khác 0 (- 3 4 (- 17 x 2 12 (- 6 x 0 5 12 5 x 2 5 x 4 x 0 8 4 5 x 12 4 + 4 = 12