-1x2 -5x -6 = 0
ax2 bx c = 0
a = -1
b = -5
c = -6
Δ = b2-4ac
Δ = -5² - (4 * -1 * -6)
Δ = 25 - (4*6)
Δ = 25 - (24)
Δ = 1 Δ > 0
-x2-5x-6=0
x = -b ∓ √Δ 2a
x' = 5 - √1 2*-1 = 5 - 1.0 -2 = 4.0 -2 = -2.0
x" = 5 + √1 2*-1 = 5 + 1.0 -2 = 6.0 -2 = -3.0
x' = -2.0
x" = -3.0
S = {x ∈ R / x' = -2.0, x" = -3.0 }