-18x2 +4x +22 = 0
ax2 bx c = 0
a = -18
b = 4
c = 22
Δ = b2-4ac
Δ = 4² - (4 * -18 * 22)
Δ = 16 - (4*-396)
Δ = 16 - (-1584)
Δ = 1600 Δ > 0
-18x2+4x+22=0
x = -b ∓ √Δ 2a
x' = -4 - √1600 2*-18 = -4 - 40.0 -36 = -44.0 -36 = 1.22222222222
x" = -4 + √1600 2*-18 = -4 + 40.0 -36 = 36.0 -36 = -1.0
x' = 396.0
x" = -324.0
S = {x ∈ R / x' = 396.0, x" = -324.0 }