Respostas

  • Usuário do Brainly
2013-08-17T22:30:03-03:00
Para calcular as raízes, determinamos os valores de \text{x} quando \text{y}=\text{f}(\text{x})=0.

Assim, \text{x}^2-8\text{x}-20=0.

Note que, \text{a}=1, \text{b}=-8 e \text{c}=-20.

Então, \text{x}=\dfrac{-(-8)\pm\sqrt{(-8)^2-4\cdot1\cdot(-20)}}{2\cdot1}=\dfrac{8\pm12}{2}

Logo, as raízes dessa função são:

\text{x}'=\dfrac{8+12}{2}=10

\text{x}"=\dfrac{8-12}{2}=-2