-18x2 -10x +8 = 0
ax2 bx c = 0
a = -18
b = -10
c = 8
Δ = b2-4ac
Δ = -10² - (4 * -18 * 8)
Δ = 100 - (4*-144)
Δ = 100 - (-576)
Δ = 676 Δ > 0
-18x2-10x+8=0
x = -b ∓ √Δ 2a
x' = 10 - √676 2*-18 = 10 - 26.0 -36 = -16.0 -36 = 0.444444444444
x" = 10 + √676 2*-18 = 10 + 26.0 -36 = 36.0 -36 = -1.0
x' = 144.0
x" = -324.0
S = {x ∈ R / x' = 144.0, x" = -324.0 }