-4x2 -19x -12 = 0
ax2 bx c = 0
a = -4
b = -19
c = -12
Δ = b2-4ac
Δ = -19² - (4 * -4 * -12)
Δ = 361 - (4*48)
Δ = 361 - (192)
Δ = 169 Δ > 0
-4x2-19x-12=0
x = -b ∓ √Δ 2a
x' = 19 - √169 2*-4 = 19 - 13.0 -8 = 6.0 -8 = -0.75
x" = 19 + √169 2*-4 = 19 + 13.0 -8 = 32.0 -8 = -4.0
x' = -12.0
x" = -64.0
S = {x ∈ R / x' = -12.0, x" = -64.0 }