Question

Quais os zeros da função f(x)=x²+x-6

A)-1 e 6 B)1 e 6 C) -1 e -6 D)1 e 6 E)0 e 1

Answer 1

Delta = 1² - 4.1.(-6)

Delta = 25

x= \frac{-1+-5}{2.1}

x'=2

x"=-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 $\sf 2~e~-3$