посчитайте ,12 минут осталось​

x² + px + 80 = 0

При x = 5:

25 +5p + 80 = 0

5p = -105

p = -21

x² - 21x + 80 = 0

Дискриминант (b = -21, c = 80)

D = b² - 4c = (-21)² - 4(80) = 441 - 320 = 121

√D = 11

x = (-b ± √D) / 2

x = (21 ± 11) / 2

x1 = (21 + 11) / 2 = 16

x2 = (21 - 11) / 2 = 5