Question

RESOLVA AS SEGUINTES EQUAÇÕES DO SEGUNDO GRAU:
a) x2 – 16 = 0
b) x2 +2x = 0
c) x2 -2x -8 = 0
d) x2 +2x -15 = 0

Answer 1

a) x² - 16 = 0 → x² = 16 → x = √16 → x = 4

b) x² + 2x = 0 → x × (x +2) = 0 x = 0

x + 2 = 0 → x = -2

c) x² - 2x - 8 = 0 → ∆ = (-2)² - 4 × 1 × (-8) → ∆ = 4 + 32 → ∆ = 36

x = -(-2) ± √36 → x = 2 ± 6

2 × 1 2

x¹ = 2 + 6 → x¹ = 8 → x¹ = 4

2 2

x¹ = 2 - 6 → x¹ = -4 → x¹ = -2

2 2

d) x² + 2x - 15 = 0 → ∆ = 2² - 4 × 1 × (-15) → ∆ = 4 + 60 → ∆ = 64

x = 2 ± √64 → x = 2 ± 8

2 × 1 2

x¹ = 2 + 8 → x¹ = 10 → x¹ = 5

2 2

x¹ = 2 - 8 → x¹ = -6 → x¹ = -3

2 2

Espero ter ajudado!!!