5x2 +12x +4 = 0
ax2 bx c = 0
a = 5
b = 12
c = 4
Δ = b2-4ac
Δ = 12² - (4 * 5 * 4)
Δ = 144 - (4*20)
Δ = 144 - (80)
Δ = 64 Δ > 0
5x2+12x+4=0
x = -b ∓ √Δ 2a
x' = -12 - √64 2*5 = -12 - 8.0 10 = -20.0 10 = -2.0
x" = -12 + √64 2*5 = -12 + 8.0 10 = -4.0 10 = -0.4
x' = -50.0
x" = -10.0
S = {x ∈ R / x' = -50.0, x" = -10.0 }