-1x2 -18x -17 = 0
ax2 bx c = 0
a = -1
b = -18
c = -17
Δ = b2-4ac
Δ = -18² - (4 * -1 * -17)
Δ = 324 - (4*17)
Δ = 324 - (68)
Δ = 256 Δ > 0
-x2-18x-17=0
x = -b ∓ √Δ 2a
x' = 18 - √256 2*-1 = 18 - 16.0 -2 = 2.0 -2 = -1.0
x" = 18 + √256 2*-1 = 18 + 16.0 -2 = 34.0 -2 = -17.0
x' = -1.0
x" = -17.0
S = {x ∈ R / x' = -1.0, x" = -17.0 }