(2х²+3y)² - (2x²-5y)² =(4x⁴ + 12x²y + 9y²) - (4x⁴ - 20x²y + 25y²) =4x⁴ + 12x²y + 9y² - 4x⁴ + 20x²y - 25y² =12x²y + 9y² + 20x²y - 25y² =32x²y - 16y²
(2х²+3y)² - (2x²-5y)² =
(4x⁴ + 12x²y + 9y²) - (4x⁴ - 20x²y + 25y²) =
4x⁴ + 12x²y + 9y² - 4x⁴ + 20x²y - 25y² =
12x²y + 9y² + 20x²y - 25y² =
32x²y - 16y²