-3x2 -9x -6 = 0
ax2 bx c = 0
a = -3
b = -9
c = -6
Δ = b2-4ac
Δ = -9² - (4 * -3 * -6)
Δ = 81 - (4*18)
Δ = 81 - (72)
Δ = 9 Δ > 0
-3x2-9x-6=0
x = -b ∓ √Δ 2a
x' = 9 - √9 2*-3 = 9 - 3.0 -6 = 6.0 -6 = -1.0
x" = 9 + √9 2*-3 = 9 + 3.0 -6 = 12.0 -6 = -2.0
x' = -9.0
x" = -18.0
S = {x ∈ R / x' = -9.0, x" = -18.0 }