-12x2 +21x +6 = 0
ax2 bx c = 0
a = -12
b = 21
c = 6
Δ = b2-4ac
Δ = 21² - (4 * -12 * 6)
Δ = 441 - (4*-72)
Δ = 441 - (-288)
Δ = 729 Δ > 0
-12x2+21x+6=0
x = -b ∓ √Δ 2a
x' = -21 - √729 2*-12 = -21 - 27.0 -24 = -48.0 -24 = 2.0
x" = -21 + √729 2*-12 = -21 + 27.0 -24 = 6.0 -24 = -0.25
x' = 288.0
x" = -36.0
S = {x ∈ R / x' = 288.0, x" = -36.0 }