13 5x 1 2x July 8, 2019 16 32 64 128 13 5x 9 2x 1 5x 13 12x 1 5x 1 ≥ 13 2x 5x 13 3 x 4 2x 1 13 4 2x 1 5x 2 13 5x 8 2x 7 1 x 5x-13 2 13-2x 5
