-12x2 +9x +3 = 0
ax2 bx c = 0
a = -12
b = 9
c = 3
Δ = b2-4ac
Δ = 9² - (4 * -12 * 3)
Δ = 81 - (4*-36)
Δ = 81 - (-144)
Δ = 225 Δ > 0
-12x2+9x+3=0
x = -b ∓ √Δ 2a
x' = -9 - √225 2*-12 = -9 - 15.0 -24 = -24.0 -24 = 1.0
x" = -9 + √225 2*-12 = -9 + 15.0 -24 = 6.0 -24 = -0.25
x' = 144.0
x" = -36.0
S = {x ∈ R / x' = 144.0, x" = -36.0 }