18. 2,25к⁴ - 2,56p⁴ = (1,5к²)² - (1,6p²)² = (1,5к² - 1,6p²)(1,5к² + 1,6p²)
Ответ: (1,5к² - 1,6p²)(1,5к² + 1,6p²)