Question

Решите уравнение (y + 1)² - 9 × y+1/2 =0

Answer 1

(y + 1)² - 9 × y+1/2 = 0

(у + 1)² - (9у + 9)/2 = 0 | ×2

2(у² + 2у + 1) - 9у - 9 = 0

2у² + 4у + 2 - 9у - 9 = 0

2у² - 5у - 7 = 0

D = b² - 4ac = 25 - 4 * 2 * (-7) = 25 + 56 = 81

y1 = (-b + √D)/2a = (5 + 9)/4 = 3,5

y2 = (-b - √D)/2a = (5 - 9)/4 = -1

Ответ: у1 = 3,5 ; у2 = -1