18x2 -x -17 = 0
ax2 bx c = 0
a = 18
b = -1
c = -17
Δ = b2-4ac
Δ = -² - (4 * 18 * -17)
Δ = 1 - (4*-306)
Δ = 1 - (-1224)
Δ = 1225 Δ > 0
18x2-x-17=0
x = -b ∓ √Δ 2a
x' = 1 - √1225 2*18 = 1 - 35.0 36 = -34.0 36 = -0.944444444444
x" = 1 + √1225 2*18 = 1 + 35.0 36 = 36.0 36 = 1.0
x' = -306.0
x" = 324.0
S = {x ∈ R / x' = -306.0, x" = 324.0 }