-6x2 -15x -6 = 0
ax2 bx c = 0
a = -6
b = -15
c = -6
Δ = b2-4ac
Δ = -15² - (4 * -6 * -6)
Δ = 225 - (4*36)
Δ = 225 - (144)
Δ = 81 Δ > 0
-6x2-15x-6=0
x = -b ∓ √Δ 2a
x' = 15 - √81 2*-6 = 15 - 9.0 -12 = 6.0 -12 = -0.5
x" = 15 + √81 2*-6 = 15 + 9.0 -12 = 24.0 -12 = -2.0
x' = -18.0
x" = -72.0
S = {x ∈ R / x' = -18.0, x" = -72.0 }