-6x2 -3x +9 = 0

ax2 bx c = 0

a = -6

b = -3

c = 9

Δ = b2-4ac

Δ = -3² - (4 * -6 * 9)

Δ = 9 - (4*-54)

Δ = 9 - (-216)

Δ = 225      Δ > 0

-6x2-3x+9=0

x = -b ∓ √Δ 2a

x' = 3 - √225 2*-6 = 3 - 15.0 -12 = -12.0 -12 = 1.0

x" = 3 + √225 2*-6 = 3 + 15.0 -12 = 18.0 -12 = -1.5

x' = 36.0

x" = -54.0

S = {x ∈ R / x' = 36.0, x" = -54.0 }