Question

1) Dada a função f (x) = x2 – 2x – 8, calcule as raízes: *
2 e 4
- 2 e 4
2 e - 4
- 2 e - 4

Answer 1

Explicação passo-a-passo:

x²-2x-8 > a = 1 / b = -2 / c = -8

±b√ - b² - 4 . a . c

_________________

2 . a

±(-2) √ - 2² - 4 . 1 . - 8

_________________

2 . 1

±(-2) √ 4 - (-32)

_____________

2

±(-2) √ 4 + 32

____________

2

±(-2) √36

_________

2

± (-2) + 6

________

2

X1 = - -2 + 6 => +2 +6 => 8 ==>> 4

_____ _____ _

2 2 2

X2 = + -2 + 6 => -2 +6 => 4 ==>> 2

______ ____ _

2 2 2

X1 = 4

X2 = 2