1) (d - 5)(9d+1)(3d-9) = (9d² + d - 45d - 5)(3d - 9) = (9d² - 44d - 5)(3d - 9) =
= 27d³ - 81d² - 132d² + 396d - 15d + 45 = 27d³ - 213d2 + 381d + 45
2) (b³ + 4b + 2)(- b³ - 4b + 2) = - (b³ + 4b + 2)(b³ + 4b - 2) =
= - [(b³ + 4b)² - 2²] = - (b⁶ + 8b⁴ + 16b² - 4) = 4 - b⁶ - 8b⁴ - 16b²
3) (x + y)(x² - 3x²y + 2xy² + y²) = x³ - 3x³y + 2x²y² + xy² + x²y - 3x²y² + 2xy³ + y³ =
= x³ - 3x³y - x²y² + xy² + x²y + 2xy³ + y³