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 = 4.0 10 = 0.4
x" = 12 + √64 2*5 = 12 + 8.0 10 = 20.0 10 = 2.0
x' = 10.0
x" = 50.0
S = {x ∈ R / x' = 10.0, x" = 50.0 }