Question

7. Quais são as raízes da equação x2+2x-8=0 A = b2 - 4.a.c x = -b/a 2a O x'=2 e X"=1 O x'=-2 e x”=4 O x'=-2 e X"=1 O x'= 2 e X"=-4
​

Answer 1

Resposta:

$\textsf{Leia abaixo}$

Explicação passo a passo:

$\mathsf{x^2 + 2x - 8 = 0}$

$\mathsf{\Delta = b^2 - 4.a.c}$

$\mathsf{\Delta = 2^2 - 4.1.(-8)}$

$\mathsf{\Delta = 4 + 32}$

$\mathsf{\Delta = 36}$

$\mathsf{x = \dfrac{-b \pm \sqrt{\Delta}}{2a} = \dfrac{-2 \pm \sqrt{36}}{2} \rightarrow \begin{cases}\mathsf{x' = \dfrac{-2 + 6}{2} = \dfrac{4}{2} = 2}\\\\\mathsf{x'' = \dfrac{-2 - 6}{2} = \dfrac{-8}{2} = -4}\end{cases}}$

$\boxed{\boxed{\mathsf{S = \{2;-4\}}}}$