Question

cacule as raízes da função f(x)= -2x²+x+1
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Answer 1

Resposta:

$\textsf{Leia abaixo}$

Explicação passo-a-passo:

$\mathsf{f(x) = -2x^2 + x + 1}$

$\mathsf{-2x^2 + x + 1 = 0}$

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

$\mathsf{\Delta = 1^2 - 4.(-2).1}$

$\mathsf{\Delta = 1 + 8}$

$\mathsf{\Delta = 9}$

$\mathsf{x = \dfrac{-b \pm \sqrt{\Delta}}{2a} = \dfrac{-1 \pm \sqrt{9}}{-4} \rightarrow \begin{cases}\mathsf{x' = \dfrac{-1 + 3}{-4} = \dfrac{2}{-4} = -\dfrac{1}{2}}\\\\\mathsf{x'' = \dfrac{-1 - 3}{-4} = \dfrac{-4}{-4} = 1}\end{cases}}$

$\boxed{\boxed{\mathsf{S = \{\:1\:;-\dfrac{1}{2}\:\}}}}$