4 9 x 3 12 July 8, 2019 16 32 64 128 9 х 3 12 4 5 9 x 1 4 4 9 x 3 12 4 7 x 9 12 3 7 2 X 4 4x 3 12x 9 0 X 4 4x 3 12x 9 4 9 x 10 x 3 12 1 3 4 9 x 12 Envelope 9 x 12 3 4 9 5 x 4 3 12 15 5 12 x 4 9 x 3 10 1 3 x 9 4 x 12 2 4 3 (- 9x 12 )- x 11x 9 4 3 (- 9x 12 )- x 13x 9 12 4 2x 9 )=- 8 x 3