-12x2 -8x +20 = 0
ax2 bx c = 0
a = -12
b = -8
c = 20
Δ = b2-4ac
Δ = -8² - (4 * -12 * 20)
Δ = 64 - (4*-240)
Δ = 64 - (-960)
Δ = 1024 Δ > 0
-12x2-8x+20=0
x = -b ∓ √Δ 2a
x' = 8 - √1024 2*-12 = 8 - 32.0 -24 = -24.0 -24 = 1.0
x" = 8 + √1024 2*-12 = 8 + 32.0 -24 = 40.0 -24 = -1.66666666667
x' = 144.0
x" = -240.0
S = {x ∈ R / x' = 144.0, x" = -240.0 }