-4x2 +23x -19 = 0
ax2 bx c = 0
a = -4
b = 23
c = -19
Δ = b2-4ac
Δ = 23² - (4 * -4 * -19)
Δ = 529 - (4*76)
Δ = 529 - (304)
Δ = 225 Δ > 0
-4x2+23x-19=0
x = -b ∓ √Δ 2a
x' = -23 - √225 2*-4 = -23 - 15.0 -8 = -38.0 -8 = 4.75
x" = -23 + √225 2*-4 = -23 + 15.0 -8 = -8.0 -8 = 1.0
x' = 76.0
x" = 16.0
S = {x ∈ R / x' = 76.0, x" = 16.0 }