Question

Encontre as solução: 3X² – X – 2 = 0 a)X1 = 1 e X2 = - 0,666 b)X1 = - 1 e X2 = - 0,666 c)X1 = - 1 e X2 = 0,666 d)X1 = 1 e X2 = + 0,666 Agradeço pela ajuda :)

Answer 1

Resposta:

A

Explicação passo-a-passo:

$3x^2-x-2=0$

$\Delta=(-1)^2-4\cdot3\cdot(-2)$

$\Delta=1+24$

$\Delta=25$

$x=\dfrac{-(-1)\pm\sqrt{25}}{2\cdot3}=\dfrac{1\pm5}{6}$

$x_1=\dfrac{1+5}{6}~\longrightarrow~x_1=\dfrac{6}{6}~\longrightarrow~x_1=1$

$x_2=\dfrac{1-5}{6}~\longrightarrow~x_2=\dfrac{-4}{6}~\longrightarrow~x_2=-0,666$

Letra A

Answer 2

⠀⠀3x² - x - 2 = 0

⠀⠀

⠀⠀⠀⠀∆ = (-1)² - 4 × 3 × (-2)

⠀⠀⠀⠀∆ = 1 + 24

⠀⠀⠀⠀∆ = 25

⠀⠀

⠀⠀$\sf x = \dfrac{1 \pm \sqrt{25}}{2 \times 3}$

⠀⠀$\sf x = \dfrac{1 \pm 5}{6}$

⠀⠀

⠀⠀$\sf x'= \dfrac{1 - 5}{6}$

⠀⠀$\sf x'= -\dfrac{4}{6}$

⠀⠀$\sf \LARGE x'= -\dfrac{2}{3}$

⠀⠀

____________________________________

⠀⠀

⠀⠀$\sf x"= \dfrac{1 + 5}{6}$

⠀⠀$\sf x"= \dfrac{6}{6}$

⠀⠀$\sf \LARGE x"= 1$

⠀⠀

⠀⠀

Espero Ter Ajudado !!