-18x2 +8x +10 = 0
ax2 bx c = 0
a = -18
b = 8
c = 10
Δ = b2-4ac
Δ = 8² - (4 * -18 * 10)
Δ = 64 - (4*-180)
Δ = 64 - (-720)
Δ = 784 Δ > 0
-18x2+8x+10=0
x = -b ∓ √Δ 2a
x' = -8 - √784 2*-18 = -8 - 28.0 -36 = -36.0 -36 = 1.0
x" = -8 + √784 2*-18 = -8 + 28.0 -36 = 20.0 -36 = -0.555555555556
x' = 324.0
x" = -180.0
S = {x ∈ R / x' = 324.0, x" = -180.0 }