-4x2 -14x -12 = 0

ax2 bx c = 0

a = -4

b = -14

c = -12

Δ = b2-4ac

Δ = -14² - (4 * -4 * -12)

Δ = 196 - (4*48)

Δ = 196 - (192)

Δ = 4      Δ > 0

-4x2-14x-12=0

x = -b ∓ √Δ 2a

x' = 14 - √4 2*-4 = 14 - 2.0 -8 = 12.0 -8 = -1.5

x" = 14 + √4 2*-4 = 14 + 2.0 -8 = 16.0 -8 = -2.0

x' = -24.0

x" = -32.0

S = {x ∈ R / x' = -24.0, x" = -32.0 }