-12x2 -7x +19 = 0

ax2 bx c = 0

a = -12

b = -7

c = 19

Δ = b2-4ac

Δ = -7² - (4 * -12 * 19)

Δ = 49 - (4*-228)

Δ = 49 - (-912)

Δ = 961      Δ > 0

-12x2-7x+19=0

x = -b ∓ √Δ 2a

x' = 7 - √961 2*-12 = 7 - 31.0 -24 = -24.0 -24 = 1.0

x" = 7 + √961 2*-12 = 7 + 31.0 -24 = 38.0 -24 = -1.58333333333

x' = 144.0

x" = -228.0

S = {x ∈ R / x' = 144.0, x" = -228.0 }