-6x2 -12x +18 = 0

ax2 bx c = 0

a = -6

b = -12

c = 18

Δ = b2-4ac

Δ = -12² - (4 * -6 * 18)

Δ = 144 - (4*-108)

Δ = 144 - (-432)

Δ = 576      Δ > 0

-6x2-12x+18=0

x = -b ∓ √Δ 2a

x' = 12 - √576 2*-6 = 12 - 24.0 -12 = -12.0 -12 = 1.0

x" = 12 + √576 2*-6 = 12 + 24.0 -12 = 36.0 -12 = -3.0

x' = 36.0

x" = -108.0

S = {x ∈ R / x' = 36.0, x" = -108.0 }