-4x2 +7x +11 = 0
ax2 bx c = 0
a = -4
b = 7
c = 11
Δ = b2-4ac
Δ = 7² - (4 * -4 * 11)
Δ = 49 - (4*-44)
Δ = 49 - (-176)
Δ = 225 Δ > 0
-4x2+7x+11=0
x = -b ∓ √Δ 2a
x' = -7 - √225 2*-4 = -7 - 15.0 -8 = -22.0 -8 = 2.75
x" = -7 + √225 2*-4 = -7 + 15.0 -8 = 8.0 -8 = -1.0
x' = 44.0
x" = -16.0
S = {x ∈ R / x' = 44.0, x" = -16.0 }