-1x2 -6x +16 = 0

ax2 bx c = 0

a = -1

b = -6

c = 16

Δ = b2-4ac

Δ = -6² - (4 * -1 * 16)

Δ = 36 - (4*-16)

Δ = 36 - (-64)

Δ = 100      Δ > 0

-x2-6x+16=0

x = -b ∓ √Δ 2a

x' = 6 - √100 2*-1 = 6 - 10.0 -2 = -4.0 -2 = 2.0

x" = 6 + √100 2*-1 = 6 + 10.0 -2 = 16.0 -2 = -8.0

x' = 2.0

x" = -8.0

S = {x ∈ R / x' = 2.0, x" = -8.0 }