-6x2 -8x +14 = 0

ax2 bx c = 0

a = -6

b = -8

c = 14

Δ = b2-4ac

Δ = -8² - (4 * -6 * 14)

Δ = 64 - (4*-84)

Δ = 64 - (-336)

Δ = 400      Δ > 0

-6x2-8x+14=0

x = -b ∓ √Δ 2a

x' = 8 - √400 2*-6 = 8 - 20.0 -12 = -12.0 -12 = 1.0

x" = 8 + √400 2*-6 = 8 + 20.0 -12 = 28.0 -12 = -2.33333333333

x' = 36.0

x" = -84.0

S = {x ∈ R / x' = 36.0, x" = -84.0 }