Question

2x² – 4x – 1 = 0

Como resolver ?

Answer 1

2x² – 4x – 1 = 0

a= 2
b= -4
c = -1

Δ = b² - 4 * a * c
Δ = (-4)² -4 * 2 * -1
Δ = 16 + 8
Δ = 24

-b +- √Δ     /2 * a

- (-4) +- √24     /2 *2
4 +- 4,89897948557    / 4

x' = 4 + 4,89897948557    / 4
x' = 8,89897948557 / 4
x' = 2,22474487139    ou 2,22

x" = 4 - 4,89897948557    / 4
x" = -0,89897948556 /4
x" = -0.22474487139     ou -0,22

Resposta : S{ 2,22  e -0,22 }