-9x2 +12x +12 = 0
ax2 bx c = 0
a = -9
b = 12
c = 12
Δ = b2-4ac
Δ = 12² - (4 * -9 * 12)
Δ = 144 - (4*-108)
Δ = 144 - (-432)
Δ = 576 Δ > 0
-9x2+12x+12=0
x = -b ∓ √Δ 2a
x' = -12 - √576 2*-9 = -12 - 24.0 -18 = -36.0 -18 = 2.0
x" = -12 + √576 2*-9 = -12 + 24.0 -18 = 12.0 -18 = -0.666666666667
x' = 162.0
x" = -54.0
S = {x ∈ R / x' = 162.0, x" = -54.0 }