-12x2 +8x -1 = 0

ax2 bx c = 0

a = -12

b = 8

c = -1

Δ = b2-4ac

Δ = 8² - (4 * -12 * -1)

Δ = 64 - (4*12)

Δ = 64 - (48)

Δ = 16      Δ > 0

-12x2+8x-1=0

x = -b ∓ √Δ 2a

x' = -8 - √16 2*-12 = -8 - 4.0 -24 = -12.0 -24 = 0.5

x" = -8 + √16 2*-12 = -8 + 4.0 -24 = -4.0 -24 = 0.166666666667

x' = 72.0

x" = 24.0

S = {x ∈ R / x' = 72.0, x" = 24.0 }