-1x2 -13x -12 = 0
ax2 bx c = 0
a = -1
b = -13
c = -12
Δ = b2-4ac
Δ = -13² - (4 * -1 * -12)
Δ = 169 - (4*12)
Δ = 169 - (48)
Δ = 121 Δ > 0
-x2-13x-12=0
x = -b ∓ √Δ 2a
x' = 13 - √121 2*-1 = 13 - 11.0 -2 = 2.0 -2 = -1.0
x" = 13 + √121 2*-1 = 13 + 11.0 -2 = 24.0 -2 = -12.0
x' = -1.0
x" = -12.0
S = {x ∈ R / x' = -1.0, x" = -12.0 }