-1x2 -13x +14 = 0
ax2 bx c = 0
a = -1
b = -13
c = 14
Δ = b2-4ac
Δ = -13² - (4 * -1 * 14)
Δ = 169 - (4*-14)
Δ = 169 - (-56)
Δ = 225 Δ > 0
-x2-13x+14=0
x = -b ∓ √Δ 2a
x' = 13 - √225 2*-1 = 13 - 15.0 -2 = -2.0 -2 = 1.0
x" = 13 + √225 2*-1 = 13 + 15.0 -2 = 28.0 -2 = -14.0
x' = 1.0
x" = -14.0
S = {x ∈ R / x' = 1.0, x" = -14.0 }