Question

Resolva as equações:


A) -4x2-2x-3

B) x2-4x-5

Me ajudem por favor e para amanhã !!

Answer 1

Resposta:

$\textsf{Leia abaixo}$

Explicação passo a passo:

$\mathsf{-4x^2 - 2x - 3 = 0}$

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

$\mathsf{\Delta = (-2)^2 - 4.(-4).(-3)}$

$\mathsf{\Delta = 4 - 48}$

$\mathsf{\Delta = -44}$

$\boxed{\boxed{\mathsf{S = \{\emptyset\}}}}$

$\mathsf{x^2 - 4x - 5 = 0}$

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

$\mathsf{\Delta = (-4)^2 - 4.1.(-5)}$

$\mathsf{\Delta = 16 + 20}$

$\mathsf{\Delta = 36}$

$\mathsf{x = \dfrac{-b \pm \sqrt{\Delta}}{2a} = \dfrac{4 \pm \sqrt{36}}{2} \rightarrow \begin{cases}\mathsf{x' = \dfrac{4 + 6}{2} = \dfrac{10}{2} = 5}\\\\\mathsf{x'' = \dfrac{4 - 6}{2} = -\dfrac{2}{2} = -1}\end{cases}}$

$\boxed{\boxed{\mathsf{S = \{5;-1\}}}}$