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 }