-6x2 +3x +9 = 0
ax2 bx c = 0
a = -6
b = 3
c = 9
Δ = b2-4ac
Δ = 3² - (4 * -6 * 9)
Δ = 9 - (4*-54)
Δ = 9 - (-216)
Δ = 225 Δ > 0
-6x2+3x+9=0
x = -b ∓ √Δ 2a
x' = -3 - √225 2*-6 = -3 - 15.0 -12 = -18.0 -12 = 1.5
x" = -3 + √225 2*-6 = -3 + 15.0 -12 = 12.0 -12 = -1.0
x' = 54.0
x" = -36.0
S = {x ∈ R / x' = 54.0, x" = -36.0 }