5x2 +16x +11 = 0
ax2 bx c = 0
a = 5
b = 16
c = 11
Δ = b2-4ac
Δ = 16² - (4 * 5 * 11)
Δ = 256 - (4*55)
Δ = 256 - (220)
Δ = 36 Δ > 0
5x2+16x+11=0
x = -b ∓ √Δ 2a
x' = -16 - √36 2*5 = -16 - 6.0 10 = -22.0 10 = -2.2
x" = -16 + √36 2*5 = -16 + 6.0 10 = -10.0 10 = -1.0
x' = -55.0
x" = -25.0
S = {x ∈ R / x' = -55.0, x" = -25.0 }