Respostas

2014-06-04T14:52:22-03:00
-x² + 4x + 1 = 0
x² - 4x - 1 = 0
Δ = b² - 4.a.c
Δ = (-4)² - 4. 1 . (-1)
Δ = 16 + 4 = 20
x = (- b ± √Δ)/2a
x = 4 ± √20/2
x' = 4 + √20/2
x' = 2 + √20
x' = 2 + √2².5
x' = 2 + 2² √5
x' = 2 + 4 √5
x' = 6√5
x'' = 4 - √20/2
x'' = 2 - √20
x'' = 2 - 2² √5
x'' = - 2√5