-4x2 +19x +23 = 0
ax2 bx c = 0
a = -4
b = 19
c = 23
Δ = b2-4ac
Δ = 19² - (4 * -4 * 23)
Δ = 361 - (4*-92)
Δ = 361 - (-368)
Δ = 729 Δ > 0
-4x2+19x+23=0
x = -b ∓ √Δ 2a
x' = -19 - √729 2*-4 = -19 - 27.0 -8 = -46.0 -8 = 5.75
x" = -19 + √729 2*-4 = -19 + 27.0 -8 = 8.0 -8 = -1.0
x' = 92.0
x" = -16.0
S = {x ∈ R / x' = 92.0, x" = -16.0 }