5x2 +6x +1 = 0
ax2 bx c = 0
a = 5
b = 6
c = 1
Δ = b2-4ac
Δ = 6² - (4 * 5 * 1)
Δ = 36 - (4*5)
Δ = 36 - (20)
Δ = 16 Δ > 0
5x2+6x+1=0
x = -b ∓ √Δ 2a
x' = -6 - √16 2*5 = -6 - 4.0 10 = -10.0 10 = -1.0
x" = -6 + √16 2*5 = -6 + 4.0 10 = -2.0 10 = -0.2
x' = -25.0
x" = -5.0
S = {x ∈ R / x' = -25.0, x" = -5.0 }