-3x2+12x-12=0

Δ = b2-4ac

Δ = 12² - (4 * -3 * -12)

Δ = 144 - (4*36)

Δ = 144 - (144)

Δ = 0      Δ = 0

x = -b 2*a

x = -12 2*-3

x = 2.0

S = {x ∈ R / x = 2.0}