25ⁿ - 2 * 10ⁿ + 4ⁿ - 9 = (5²ⁿ - 2 * 5ⁿ * 2ⁿ + 2²ⁿ) - 3² = (5ⁿ - 2ⁿ)² - 3² =
= (5ⁿ - 2ⁿ + 3)(5ⁿ - 2ⁿ - 3)
25ⁿ - 2 * 10ⁿ + 4ⁿ - 9 = (5²ⁿ - 2 * 5ⁿ * 2ⁿ + 2²ⁿ) - 3² = (5ⁿ - 2ⁿ)² - 3² =
= (5ⁿ - 2ⁿ + 3)(5ⁿ - 2ⁿ - 3)