Question

Найдите сумму и произведение корней уравнения
x^2-14x-11=0

Answer 1

D = 196+44 = 240
√240 = 4√15
х₁ = 14-4√15 / 2 = 2(7-2√15) / 2 = 7-2√15
х₂ = 14+4√15 / 2 = 2(7+2√15) / 2 = 7+2√15

х₁+х₂ = (7-2√15)+(7+2√15) = 7-2√15+7+2√15 = 14

х₁*х₂ = (7-2√15)(7+2√15) = 7² - (2√15)² = 49-4*15 = 49 - 60 = -11