Question

help me please!!!!!!!!​

Answer 1

Explicação passo-a-passo:

7) Determinar Conjunto Solução da equação:

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

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

$\mathsf{2x^2 = 8~~\cdot(-1)}$

$\mathsf{x^2 = \dfrac{8}{2}}$

$\mathsf{x^2 = 4}$

$\mathsf{x = \sqrt{4}}$

$\mathsf{x = \pm 2}$

$\boxed{\mathsf{S = \left\{- 2 \: \: ; \: \: 2 \: \right\}}}$

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8) Determinar Conjunto Solução da equação

$\mathsf{x^2 + 6x + 8 = 0}$

$\mathsf{a = 1~~b = 6~~ c = 8}$

$\mathsf{\Delta= b^2 - 4ac}$

$\mathsf{\Delta = 6^2 - 4\cdot1\cdot8}$

$\mathsf{\Delta = 36 - 32}$

$\mathsf{\Delta = 4}$

$\mathsf{x = \dfrac{- b \pm \sqrt{\Delta}}{2a}}$

$\mathsf{x = \dfrac{- 6 \pm \sqrt{4}}{2\cdot1}}$

$\mathsf{x = \dfrac{- 6 \pm 2}{2}}$

$\mathsf{• \: \: x' = \dfrac{- 6 + 2}{2} = - \dfrac{4}{2} = - 2}$

$\mathsf{• \: \: x" = \dfrac{- 6 - 2}{2} = - \dfrac{8}{2} = - 4}$

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