-6x2 +3x +18 = 0
ax2 bx c = 0
a = -6
b = 3
c = 18
Δ = b2-4ac
Δ = 3² - (4 * -6 * 18)
Δ = 9 - (4*-108)
Δ = 9 - (-432)
Δ = 441 Δ > 0
-6x2+3x+18=0
x = -b ∓ √Δ 2a
x' = -3 - √441 2*-6 = -3 - 21.0 -12 = -24.0 -12 = 2.0
x" = -3 + √441 2*-6 = -3 + 21.0 -12 = 18.0 -12 = -1.5
x' = 72.0
x" = -54.0
S = {x ∈ R / x' = 72.0, x" = -54.0 }