2 c 3 18 July 8, 2019 16 32 64 128 2 3 c 18 )= 7 2 2c 3 )= 10c 18 C 3 9c 2 18c A 3 2 b c 3 18 0 =- 20 c 3 2 180 C 3 3c 2 6c 18 2 3 c 1 2 3 ca C 3 18 1 2 3 c