18x2 +16x -2 = 0
ax2 bx c = 0
a = 18
b = 16
c = -2
Δ = b2-4ac
Δ = 16² - (4 * 18 * -2)
Δ = 256 - (4*-36)
Δ = 256 - (-144)
Δ = 400 Δ > 0
18x2+16x-2=0
x = -b ∓ √Δ 2a
x' = -16 - √400 2*18 = -16 - 20.0 36 = -36.0 36 = -1.0
x" = -16 + √400 2*18 = -16 + 20.0 36 = 4.0 36 = 0.111111111111
x' = -324.0
x" = 36.0
S = {x ∈ R / x' = -324.0, x" = 36.0 }