18x2 +13x +2 = 0
ax2 bx c = 0
a = 18
b = 13
c = 2
Δ = b2-4ac
Δ = 13² - (4 * 18 * 2)
Δ = 169 - (4*36)
Δ = 169 - (144)
Δ = 25 Δ > 0
18x2+13x+2=0
x = -b ∓ √Δ 2a
x' = -13 - √25 2*18 = -13 - 5.0 36 = -18.0 36 = -0.5
x" = -13 + √25 2*18 = -13 + 5.0 36 = -8.0 36 = -0.222222222222
x' = -162.0
x" = -72.0
S = {x ∈ R / x' = -162.0, x" = -72.0 }