-12x2 +12x +9 = 0
ax2 bx c = 0
a = -12
b = 12
c = 9
Δ = b2-4ac
Δ = 12² - (4 * -12 * 9)
Δ = 144 - (4*-108)
Δ = 144 - (-432)
Δ = 576 Δ > 0
-12x2+12x+9=0
x = -b ∓ √Δ 2a
x' = -12 - √576 2*-12 = -12 - 24.0 -24 = -36.0 -24 = 1.5
x" = -12 + √576 2*-12 = -12 + 24.0 -24 = 12.0 -24 = -0.5
x' = 216.0
x" = -72.0
S = {x ∈ R / x' = 216.0, x" = -72.0 }