Question

Encontre as raízes da equação:
7x²+13x-2=0
a) 1/7 e 2
b) 1/7 e 3
c) 1/7 e -2
d) 2/17 e 3

Answer 1

Alt c)

7x² + 13x - 2 = 0

a = 7

b = 13

c = -2

Δ = b² - 4.a.c

Δ = (13)² - 4.7.(-2)

Δ = 169 - (-56)

Δ = 169 + 56

Δ = 225

x = -b ± √Δ / 2.a

x = -13 ± √225 / 2.7

x = -13 ± 15 / 14

x¹ = -13 - 15 / 14

x¹ = -28 / 14

x¹ = -2

x² = -13 + 15 / 14

x² = 2 / 14

x² = 1/7