Question

x ao quadrado menos dois x menos 8 menor igual a zero

Answer 1

x² - 2x - 8 = 0

Resolvendo por Bháskara:

$x = \dfrac{-b \pm \sqrt{b^2 -4*a*c}}{2*a}$


Δ = b²−4ac
Δ = (−2)²−4⋅1⋅−8
Δ = 4+32
Δ = 36

$x = \dfrac{-b \pm \sqrt{\Delta}}{2*a}\\ \\ \\x = \dfrac{-(-2) \pm \sqrt{36}}{2*1}\\ \\ \\x = \dfrac{2 \pm 6}{2}\\ \\ \\ x' = \dfrac{2 + 6}{2}\\ \\ \\ x' = \dfrac{8}{2}\\ \\ \\ x' = 4\\ \\ \\ x'' = \dfrac{2 - 6}{2}\\ \\ \\x'' = \dfrac{-4}{2}\\ \\ \\ x'' = -2$

S = {4, -2}