-4x2 -18x -14 = 0
ax2 bx c = 0
a = -4
b = -18
c = -14
Δ = b2-4ac
Δ = -18² - (4 * -4 * -14)
Δ = 324 - (4*56)
Δ = 324 - (224)
Δ = 100 Δ > 0
-4x2-18x-14=0
x = -b ∓ √Δ 2a
x' = 18 - √100 2*-4 = 18 - 10.0 -8 = 8.0 -8 = -1.0
x" = 18 + √100 2*-4 = 18 + 10.0 -8 = 28.0 -8 = -3.5
x' = -16.0
x" = -56.0
S = {x ∈ R / x' = -16.0, x" = -56.0 }