-1x2 -15x -14 = 0
ax2 bx c = 0
a = -1
b = -15
c = -14
Δ = b2-4ac
Δ = -15² - (4 * -1 * -14)
Δ = 225 - (4*14)
Δ = 225 - (56)
Δ = 169 Δ > 0
-x2-15x-14=0
x = -b ∓ √Δ 2a
x' = 15 - √169 2*-1 = 15 - 13.0 -2 = 2.0 -2 = -1.0
x" = 15 + √169 2*-1 = 15 + 13.0 -2 = 28.0 -2 = -14.0
x' = -1.0
x" = -14.0
S = {x ∈ R / x' = -1.0, x" = -14.0 }