18x2 +3x -6 = 0
ax2 bx c = 0
a = 18
b = 3
c = -6
Δ = b2-4ac
Δ = 3² - (4 * 18 * -6)
Δ = 9 - (4*-108)
Δ = 9 - (-432)
Δ = 441 Δ > 0
18x2+3x-6=0
x = -b ∓ √Δ 2a
x' = -3 - √441 2*18 = -3 - 21.0 36 = -24.0 36 = -0.666666666667
x" = -3 + √441 2*18 = -3 + 21.0 36 = 18.0 36 = 0.5
x' = -216.0
x" = 162.0
S = {x ∈ R / x' = -216.0, x" = 162.0 }