Question

Помогите (5х^2 + 2у^2 ) 2 – (5х^2 + 2у^2 )(5х^2 – 2у^2)

Answer 1

Первый способ :

(5x² + 2y²)² - (5x² + 2y²)(5x² - 2y²) = (5x² + 2y²)(5x² + 2y² - 5x² + 2y²) =

= (5x² + 2y²) * 4y² = 20x²y² + 8y⁴

Второй способ :

(5x² + 2y²)² - (5x² + 2y²)(5x² - 2y²) = 25x⁴ + 20x²y² + 4y⁴ - 25x⁴ + 4y⁴ =

= 20x²y² + 8y⁴