5x2 +11x +6 = 0
ax2 bx c = 0
a = 5
b = 11
c = 6
Δ = b2-4ac
Δ = 11² - (4 * 5 * 6)
Δ = 121 - (4*30)
Δ = 121 - (120)
Δ = 1 Δ > 0
5x2+11x+6=0
x = -b ∓ √Δ 2a
x' = -11 - √1 2*5 = -11 - 1.0 10 = -12.0 10 = -1.2
x" = -11 + √1 2*5 = -11 + 1.0 10 = -10.0 10 = -1.0
x' = -30.0
x" = -25.0
S = {x ∈ R / x' = -30.0, x" = -25.0 }