... = x2 – x + 1b) C = 8x9 – 9x 8 + 1 = 8x9 – 8 - 9x 8 + 9 = 8( x9 – 1) – 9(x 8 – 1) = 8( x – 1)(x 8 + x7 + + 1) – 9(x – 1)(x7 + x6 + + 1) = (x – 1)(8x 8 – x7 – x6 – x5 ... x 88 + x77 + + x11 + 1 chia hết cho g(x) = x9 + x 8 + x7 + + x + 1Ta có: f(x) – g(x) = x99 – x9 + x 88 – x 8 + x77 – x7 + + x11 – x + 1 – 1 = x9(x90 – 1) + x 8 (x 80 ... 9123 8 n00 01 2 31 . Đặt n99 9123 = a ⇒ 10n = a + 1D = n99 9123. 10n + 2 + 8. 10n + 1 + 1 = a . 100 . 10n + 80 . 10n + 1 = 100a(a + 1) + 80 (a + 1) + 1 = 100a2 + 180 a + 81 ...