Question

Sejam x' e x" as raízes da equação do 2º grau x2 + 2x - 15 = 0. Determine a soma dos inversos
de x' e x".
​

Answer 1

Resposta ↓

Valor da soma de x' e x" = (- 2)

Explicação passo-a-passo:

x² + 2x - 15 = 0

Coeficientes :

a = 1

b = 2

c = - 15

Δ = b² - 4.a.c

Δ = 2² - 4.1.(-15)

Δ = 4 + 60

Δ = 64

$x = \cfrac{-b\pm\sqrt{\Delta} }{2.a} \\\\\\x = \cfrac{-2\pm8}{2} \\\\\\x' = \cfrac{-2-8}{2} \\\\\\x' = \cfrac{-10}{2} \\\\\\x' = - 5\\\\\\x" = \cfrac{-2+8}{2} \\\\\\x" = \cfrac{6}{2} \\\\\\x" = 3$

s = {-5, 3}

Somando :

- 5 + 3

= -2