7 х 3 21 July 8, 2019 16 32 64 128 7 x 3 21 7 x 3 )=- 21 7x Х 7 3 216 7 3 x 21 4 2 7 x 3 21 7 9 x 3 21 2 3/7 х/7 3 1/7 7 х 3
