... 1 - . 11 1 by the 1-digit number 6 - 1 gives ( 6- l)(b- l)(b- 1 )-( 6- l)(b- l)(b- I)(, = bn - 1. Corollary. For any integer b and any positive integers m and n, we have bmn - ... m. Factor 315 - 1 and 324 - 1. Factor 512 - 1. Factor lo5 - 1, lo6 - 1 and lo8 - 1. Factor 233 - 1 and 221 - 1. Factor 215 - 1, 230 - 1, and 260 - 1. (a) Prove ... 0-, I-, 2- or 3-power, mul- tiplied by 3 to the 0- or l-power, times 5 to the 0-, l- or 2-power, times 7 to the 0- or 1- power. The number of possible divisors is thus the prod-...