-1x2 -14x -13 = 0
ax2 bx c = 0
a = -1
b = -14
c = -13
Δ = b2-4ac
Δ = -14² - (4 * -1 * -13)
Δ = 196 - (4*13)
Δ = 196 - (52)
Δ = 144 Δ > 0
-x2-14x-13=0
x = -b ∓ √Δ 2a
x' = 14 - √144 2*-1 = 14 - 12.0 -2 = 2.0 -2 = -1.0
x" = 14 + √144 2*-1 = 14 + 12.0 -2 = 26.0 -2 = -13.0
x' = -1.0
x" = -13.0
S = {x ∈ R / x' = -1.0, x" = -13.0 }