-6x2 +2x +20 = 0
ax2 bx c = 0
a = -6
b = 2
c = 20
Δ = b2-4ac
Δ = 2² - (4 * -6 * 20)
Δ = 4 - (4*-120)
Δ = 4 - (-480)
Δ = 484 Δ > 0
-6x2+2x+20=0
x = -b ∓ √Δ 2a
x' = -2 - √484 2*-6 = -2 - 22.0 -12 = -24.0 -12 = 2.0
x" = -2 + √484 2*-6 = -2 + 22.0 -12 = 20.0 -12 = -1.66666666667
x' = 72.0
x" = -60.0
S = {x ∈ R / x' = 72.0, x" = -60.0 }