18x2 +11x -10 = 0
ax2 bx c = 0
a = 18
b = 11
c = -10
Δ = b2-4ac
Δ = 11² - (4 * 18 * -10)
Δ = 121 - (4*-180)
Δ = 121 - (-720)
Δ = 841 Δ > 0
18x2+11x-10=0
x = -b ∓ √Δ 2a
x' = -11 - √841 2*18 = -11 - 29.0 36 = -40.0 36 = -1.11111111111
x" = -11 + √841 2*18 = -11 + 29.0 36 = 18.0 36 = 0.5
x' = -360.0
x" = 162.0
S = {x ∈ R / x' = -360.0, x" = 162.0 }