Respostas

  • Usuário do Brainly
2014-07-15T17:21:36-03:00
X² - 4x - 5 = 0
Δ = b² - 4 . a . c
Δ = (- 4)² - 4 . 1 . (- 5)
Δ = 16 + 20
Δ = 36

x = (- b ± √Δ)/(2 . a)
x = (- (- 4) ± √36)/(2 . 1)
x = (4 ± 6)/2

x' = (4 + 6)/2
x' = 10/2
x' = 5

x'' = (4 - 6)/2
x'' = - 2/2
x'' = - 1

S= {- 1, 5}
1 5 1