-18x2 -17x +13 = 0
ax2 bx c = 0
a = -18
b = -17
c = 13
Δ = b2-4ac
Δ = -17² - (4 * -18 * 13)
Δ = 289 - (4*-234)
Δ = 289 - (-936)
Δ = 1225 Δ > 0
-18x2-17x+13=0
x = -b ∓ √Δ 2a
x' = 17 - √1225 2*-18 = 17 - 35.0 -36 = -18.0 -36 = 0.5
x" = 17 + √1225 2*-18 = 17 + 35.0 -36 = 52.0 -36 = -1.44444444444
x' = 162.0
x" = -468.0
S = {x ∈ R / x' = 162.0, x" = -468.0 }