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 = -44.0 44 = -1.0
x" = -4 + √1600 2*22 = -4 + 40.0 44 = 36.0 44 = 0.818181818182
x' = -484.0
x" = 396.0
S = {x ∈ R / x' = -484.0, x" = 396.0 }