18x2 +23x -6 = 0
ax2 bx c = 0
a = 18
b = 23
c = -6
Δ = b2-4ac
Δ = 23² - (4 * 18 * -6)
Δ = 529 - (4*-108)
Δ = 529 - (-432)
Δ = 961 Δ > 0
18x2+23x-6=0
x = -b ∓ √Δ 2a
x' = -23 - √961 2*18 = -23 - 31.0 36 = -54.0 36 = -1.5
x" = -23 + √961 2*18 = -23 + 31.0 36 = 8.0 36 = 0.222222222222
x' = -486.0
x" = 72.0
S = {x ∈ R / x' = -486.0, x" = 72.0 }