18x2 +19x +1 = 0
ax2 bx c = 0
a = 18
b = 19
c = 1
Δ = b2-4ac
Δ = 19² - (4 * 18 * 1)
Δ = 361 - (4*18)
Δ = 361 - (72)
Δ = 289 Δ > 0
18x2+19x+1=0
x = -b ∓ √Δ 2a
x' = -19 - √289 2*18 = -19 - 17.0 36 = -36.0 36 = -1.0
x" = -19 + √289 2*18 = -19 + 17.0 36 = -2.0 36 = -0.0555555555556
x' = -324.0
x" = -18.0
S = {x ∈ R / x' = -324.0, x" = -18.0 }