-3x2 +15x -12 = 0
ax2 bx c = 0
a = -3
b = 15
c = -12
Δ = b2-4ac
Δ = 15² - (4 * -3 * -12)
Δ = 225 - (4*36)
Δ = 225 - (144)
Δ = 81 Δ > 0
-3x2+15x-12=0
x = -b ∓ √Δ 2a
x' = -15 - √81 2*-3 = -15 - 9.0 -6 = -24.0 -6 = 4.0
x" = -15 + √81 2*-3 = -15 + 9.0 -6 = -6.0 -6 = 1.0
x' = 36.0
x" = 9.0
S = {x ∈ R / x' = 36.0, x" = 9.0 }