Question

Determine o discriminante (delta) em cada equação do 2º grau: a) x2 + 6x – 1 = 0 b) x² + 9x + 3 = 0 c) 2x² + 9x + 12 = 0 d) x² + 6x + 9 = 0

Answer 1

Resposta:

1. ∆ = 40
2. ∆ = 69
3. ∆ = −15
4. ∆=0

Explicação passo-a-passo:

a)

x² + 6x − 1 = 0

a =1

b =6

c = −1

∆ = b² − 4 × a × c

∆ = 6² − 4 × 1 × (−1)

∆ = 36 + 4

∆ = 40

b)

x² + 9x + 3 = 0

a =1

b =9

c =3

∆ = b² − 4 × a × c

∆ = 9² − 4 × 1 × 3

∆ = 81 − 12

∆ = 69

c)

2x² + 9x + 12 = 0

a =2

b =9

c = 12

∆ = b² − 4 × a × c

∆ = 9² − 4 × 2 × 12

∆ = 81 − 96

∆ = −15

d)

x² + 6x + 9 = 0

a =1

b =6

c =9

∆ = b² − 4 × a × c

∆ = 6² − 4 × 1 × 9

∆ = 36 − 36

∆=0