-6x2 +20x -6 = 0

ax2 bx c = 0

a = -6

b = 20

c = -6

Δ = b2-4ac

Δ = 20² - (4 * -6 * -6)

Δ = 400 - (4*36)

Δ = 400 - (144)

Δ = 256      Δ > 0

-6x2+20x-6=0

x = -b ∓ √Δ 2a

x' = -20 - √256 2*-6 = -20 - 16.0 -12 = -36.0 -12 = 3.0

x" = -20 + √256 2*-6 = -20 + 16.0 -12 = -4.0 -12 = 0.333333333333

x' = 108.0

x" = 12.0

S = {x ∈ R / x' = 108.0, x" = 12.0 }