-6x2 -9x -3 = 0

ax2 bx c = 0

a = -6

b = -9

c = -3

Δ = b2-4ac

Δ = -9² - (4 * -6 * -3)

Δ = 81 - (4*18)

Δ = 81 - (72)

Δ = 9      Δ > 0

-6x2-9x-3=0

x = -b ∓ √Δ 2a

x' = 9 - √9 2*-6 = 9 - 3.0 -12 = 6.0 -12 = -0.5

x" = 9 + √9 2*-6 = 9 + 3.0 -12 = 12.0 -12 = -1.0

x' = -18.0

x" = -36.0

S = {x ∈ R / x' = -18.0, x" = -36.0 }