-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 }