Question

x ao quadrado menos 2x menos 4 e igual a 0

Answer 1

x^2 - 2x - 4 = 0
a = 1 ; b = -2 ; c = -4
Δ = (-2)^2 - 4x1x(-4) = 4 + 16 = 20 => √Δ = 2√5

x = -(-2) +/- 2√5/2.1
x = 2 +/- 2√5/2

x' = 2 + 2√5/2 = 1 + √5
x'' = 2 - 2√5/2 = 1 - √5

S = {1 -√5 , 1 + √5}