-3x2 -15x +18 = 0
ax2 bx c = 0
a = -3
b = -15
c = 18
Δ = b2-4ac
Δ = -15² - (4 * -3 * 18)
Δ = 225 - (4*-54)
Δ = 225 - (-216)
Δ = 441 Δ > 0
-3x2-15x+18=0
x = -b ∓ √Δ 2a
x' = 15 - √441 2*-3 = 15 - 21.0 -6 = -6.0 -6 = 1.0
x" = 15 + √441 2*-3 = 15 + 21.0 -6 = 36.0 -6 = -6.0
x' = 9.0
x" = -54.0
S = {x ∈ R / x' = 9.0, x" = -54.0 }