1. (x - 2)(x² + 2x + 4) - (1 + x)(x² - x + 1) = x³ - 2³- (1³ + x³) = -2³ - 1³= -8 - 1 = -9
2. (x - 3)(x² + 3x + 9) - (x + 1)(x - 1)(x - 2) = x³ - 3³ - (x² - 1²)(x - 2) = x³ - 3³ - (x³ - x - 2x² + 2) = x³ - 27 - x³ + x + 2x² - 2 = 2x² + x - 29
3. a(a - 3)(a + 3) - (a + 2)(a² - 2a + 4) = a(a² - 3²) - (a³ + 2³) = a³ - 9a - a³ - 8 = -9a - 8