-6x2 -18x -12 = 0
ax2 bx c = 0
a = -6
b = -18
c = -12
Δ = b2-4ac
Δ = -18² - (4 * -6 * -12)
Δ = 324 - (4*72)
Δ = 324 - (288)
Δ = 36 Δ > 0
-6x2-18x-12=0
x = -b ∓ √Δ 2a
x' = 18 - √36 2*-6 = 18 - 6.0 -12 = 12.0 -12 = -1.0
x" = 18 + √36 2*-6 = 18 + 6.0 -12 = 24.0 -12 = -2.0
x' = -36.0
x" = -72.0
S = {x ∈ R / x' = -36.0, x" = -72.0 }