X 7 9 4 23 8 July 8, 2019 16 32 64 128 X chia 7 phần 9 4 23 8 23 4 x 9 )= 7 x 8 )- 1 X chia 7 9 4 23 8 9 x 8 = 9) (x - 7)/9 = (4 - x)/7
