-4x2 -11x +3 = 0

ax2 bx c = 0

a = -4

b = -11

c = 3

Δ = b2-4ac

Δ = -11² - (4 * -4 * 3)

Δ = 121 - (4*-12)

Δ = 121 - (-48)

Δ = 169      Δ > 0

-4x2-11x+3=0

x = -b ∓ √Δ 2a

x' = 11 - √169 2*-4 = 11 - 13.0 -8 = -2.0 -8 = 0.25

x" = 11 + √169 2*-4 = 11 + 13.0 -8 = 24.0 -8 = -3.0

x' = 4.0

x" = -48.0

S = {x ∈ R / x' = 4.0, x" = -48.0 }