Question

Quais os zeros da função f(x) = x² + x - 6?

Answer 1

delta = 1² + 24 
delta = 25
x = -1 +-raiz de 25 / 2
x = -1 +- 5/2
x´= -1+5/2 = 4/2 = 2
x ´´ = -1-5/2 = -6/2 = -3

Answer 2

Explicação passo-a-passo:

$\sf x^2+x-6=0$

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

$\sf \Delta=1+24$

$\sf \Delta=25$

$\sf x=\dfrac{-1\pm\sqrt{25}}{2\cdot1}=\dfrac{-1\pm5}{2}$

$\sf x'=\dfrac{-1+5}{2}~\Rightarrow~x'=\dfrac{4}{2}~\Rightarrow~\red{x'=2}$

$\sf x"=\dfrac{-1-5}{2}~\Rightarrow~x"=\dfrac{-6}{2}~\Rightarrow~\red{x"=-3}$

Os zeros dessa função são $\sf 2~e~-3$