Resposta :
x² + 6x + 8 = 0
a = 1, b = 6, c = 8
Δ = b² - 4 · a · c
Δ = 6² - 4 · 1 · 8
Δ = 36 - 32
Δ = 4
x = - b ± √Δ / 2 · a
x = - 6 ± √4 / 2 · 1
x = - 6 ± 2 / 2
x' = - 6 + 2 / 2 = - 4 / 2 = - 2
x'' = - 6 - 2 / 2 = - 8 / 2 = - 4
X) {– 2, – 4}
b) {– 2, 4}
c) {2, 4}
d) {– 4, 2}