Решите уравнение: 1) 3x² – 15 = 0; 2) 4x² – 7x = 0; 3) x² + 8x – 9 = 0; 4) 12x²-5x-2=0;

Решим уравнения: 1) 3x² - 15 = 0 3x² = 15 x² = 5 x₁ = √5 x₂ = -√5 Ответ: x₁ = √5, x₂ = -√5 2) 4x² - 7x = 0 x(4x - 7) = 0 x₁ = 0 4x - 7 = 0 4x = 7 x₂ = 7/4 = 1,75 Ответ: x₁ = 0, x₂ = 1,75 3) x² + 8x - 9 = 0 D = b² - 4ac = 8² - 4 * 1 * (-9) = 64 + 36 = 100 x₁ = (-b + √D) / 2a = (-8 + √100) / 2 * 1 = (-8 + 10) / 2 = 2 / 2 = 1 x₂ = (-b - √D) / 2a = (-8 - √100) / 2 * 1 = (-8 - 10) / 2 = -18 / 2 = -9 Ответ: x₁ = 1, x₂ = -9 4) 12x² - 5x - 2 = 0 D = b² - 4ac = (-5)² - 4 * 12 * (-2) = 25 + 96 = 121 x₁ = (-b + √D) / 2a = (5 + √121) / 2 * 12 = (5 + 11) / 24 = 16 / 24 = 2/3 x₂ = (-b - √D) / 2a = (5 - √121) / 2 * 12 = (5 - 11) / 24 = -6 / 24 = -1/4 Ответ: x₁ = 2/3, x₂ = -1/4