-9x2 -19x -2 = 0
ax2 bx c = 0
a = -9
b = -19
c = -2
Δ = b2-4ac
Δ = -19² - (4 * -9 * -2)
Δ = 361 - (4*18)
Δ = 361 - (72)
Δ = 289 Δ > 0
-9x2-19x-2=0
x = -b ∓ √Δ 2a
x' = 19 - √289 2*-9 = 19 - 17.0 -18 = 2.0 -18 = -0.111111111111
x" = 19 + √289 2*-9 = 19 + 17.0 -18 = 36.0 -18 = -2.0
x' = -9.0
x" = -162.0
S = {x ∈ R / x' = -9.0, x" = -162.0 }