Нужно! у простите выражение : (x-4)(x+8)-x^2 7c^2-5(2c-1)^2 (x+9)^2-(x-5)(x+5) (y+3)(y^2-2y+4)

1) (x - 4)(x + 8) - x² = (x² + 8x - 4x - 32) - x² = 4x - 32
2) 7c² - 5(2c - 1)² = 7c² - 5(2c - 1)(2c - 1) = 7c² - 5(4c² - 2c - 2c + 1) = 7c² - 20c² - 10c - 10c + 5 = -13c² - 20c + 5
3) (x + 9)² - (x - 5)(x + 5) = (x + 9)(x + 9) - (x² + 5x - 5x - 25) = x² + 9x + 9x + 81 - x² - 5x + 5x + 25 = 18x + 106
4) (y + 3)(y² - 2y + 4) = y³ - 2y² + 4y + 3y² - 6y + 12 = y³ + y² - 2y + 12