-3x2 +3x +18 = 0
ax2 bx c = 0
a = -3
b = 3
c = 18
Δ = b2-4ac
Δ = 3² - (4 * -3 * 18)
Δ = 9 - (4*-54)
Δ = 9 - (-216)
Δ = 225 Δ > 0
-3x2+3x+18=0
x = -b ∓ √Δ 2a
x' = -3 - √225 2*-3 = -3 - 15.0 -6 = -18.0 -6 = 3.0
x" = -3 + √225 2*-3 = -3 + 15.0 -6 = 12.0 -6 = -2.0
x' = 27.0
x" = -18.0
S = {x ∈ R / x' = 27.0, x" = -18.0 }