Question

Dada a função f(x)= ) x² - x -6 = 0 quais as suas raízes reais. *

2 e 3

-2 e 3

2 e -3

-2 e -3

0 e 3​

Answer 1

Resposta:

-2 e 3

Explicação passo-a-passo:

$x^2-x-6=0$

$\Delta=(-1)^2-4\cdot1\cdot(-6)$

$\Delta=1+24$

$\Delta=25$

$x=\dfrac{-(-1)\pm\sqrt{25}}{2\cdot1}$

$x=\dfrac{1\pm5}{2}$

$x'=\dfrac{1+5}{2}~\longrightarrow~x'=\dfrac{6}{2}~\longrightarrow~x'=3$

$x"=\dfrac{1-5}{2}~\longrightarrow~x"=\dfrac{-4}{2}~\longrightarrow~x"=-2$