Решите уравнение

(3+6x) (3x-9) = 0 25 - X во 2 степени = 0

(3 + 6x) (3x - 9) = 0

9x - 27 + 18x² - 54x = 0

18x² - 45x - 27 = 0

D = b² - 4ac = ( - 45) ² - 4 * 18 * ( - 27) = 2025 + 1944 = 3969 = 63²

x₁ = 45 + 63 / 36 = 108 / 36 = 3

x₂ = 45 - 63 / 36 = - 18 / 36 = - 0,5

25 - x² = 0

- x² + 25 = 0

x² - 25 = 0

D = b² - 4ac = 0 - 4 * 1 * ( - 25) = 100 = 10²

x₁ = 0 + 10 / 2 = 5

x₂ = 0 - 10 / 2 = - 5