-6x2 +9x +6 = 0
ax2 bx c = 0
a = -6
b = 9
c = 6
Δ = b2-4ac
Δ = 9² - (4 * -6 * 6)
Δ = 81 - (4*-36)
Δ = 81 - (-144)
Δ = 225 Δ > 0
-6x2+9x+6=0
x = -b ∓ √Δ 2a
x' = -9 - √225 2*-6 = -9 - 15.0 -12 = -24.0 -12 = 2.0
x" = -9 + √225 2*-6 = -9 + 15.0 -12 = 6.0 -12 = -0.5
x' = 72.0
x" = -18.0
S = {x ∈ R / x' = 72.0, x" = -18.0 }