Вправи 888 - 1000 » 965 (г-ґ)

г) 2x(3x + 4) = 4x2 + 5x + 27; 6х2 + 8х – 4х2 – 5х – 27 = 0; 2x2 + Зx – 27 = 0; x = (-3 ± √(9+216))/4 = (-3 ± 15)/4; x1 = (-3+15)/4 = 3; x2 = (-3-15)/4 = –4,5. Відповідь: 3; –4,5. ґ) (x + 4)(2х – 3) – (5x – 6)(x – 3) = 10; 2x2 – Зx + 8x – 12 – 5x2 + 15x + 6x – 18 – 10 = 0; –Зx2 + 26x – 40 = 0; Зx2 – 26x + 40 = 0; x = (13 ± √(169-120))/3 = (13 ± 7)/3; x1 = 20/3 = 62/3; x2 = 2; Відповідь: 62/3; 2.