Question

Formula Bascara.
x²+5x-9=0

Answer 1

 x² + 5x - 9 = 0

a = 1
b = + 5 
c = - 9

Δ = b² - 4.a.c
Δ = 5² - 4.1. (- 9)
Δ = 25 + 36
Δ = 61

x = - b + - √Δ/2a
x = - 5 + - √61/2.1
x = - 5 + - 7,810250/2

x' = - 5 - 7,810250 / 2 ⇒ x' = - 12,810250/2 ⇒ x' = - 6,405125 ⇒ x' = ≈ - 6,40
x" = - 5 + 7,810250/2 ⇒ x" = + 2,810250/2 ⇒ x" = 1,405125⇒ x" = ≈ 1,40

S = { - 6,40 e + 1,40 }