22x2 -4x -18 = 0
ax2 bx c = 0
a = 22
b = -4
c = -18
Δ = b2-4ac
Δ = -4² - (4 * 22 * -18)
Δ = 16 - (4*-396)
Δ = 16 - (-1584)
Δ = 1600 Δ > 0
22x2-4x-18=0
x = -b ∓ √Δ 2a
x' = 4 - √1600 2*22 = 4 - 40.0 44 = -36.0 44 = -0.818181818182
x" = 4 + √1600 2*22 = 4 + 40.0 44 = 44.0 44 = 1.0
x' = -396.0
x" = 484.0
S = {x ∈ R / x' = -396.0, x" = 484.0 }