-4x2 +15x -11 = 0
ax2 bx c = 0
a = -4
b = 15
c = -11
Δ = b2-4ac
Δ = 15² - (4 * -4 * -11)
Δ = 225 - (4*44)
Δ = 225 - (176)
Δ = 49 Δ > 0
-4x2+15x-11=0
x = -b ∓ √Δ 2a
x' = -15 - √49 2*-4 = -15 - 7.0 -8 = -22.0 -8 = 2.75
x" = -15 + √49 2*-4 = -15 + 7.0 -8 = -8.0 -8 = 1.0
x' = 44.0
x" = 16.0
S = {x ∈ R / x' = 44.0, x" = 16.0 }