-1x2 +9x -14 = 0
ax2 bx c = 0
a = -1
b = 9
c = -14
Δ = b2-4ac
Δ = 9² - (4 * -1 * -14)
Δ = 81 - (4*14)
Δ = 81 - (56)
Δ = 25 Δ > 0
-x2+9x-14=0
x = -b ∓ √Δ 2a
x' = -9 - √25 2*-1 = -9 - 5.0 -2 = -14.0 -2 = 7.0
x" = -9 + √25 2*-1 = -9 + 5.0 -2 = -4.0 -2 = 2.0
x' = 7.0
x" = 2.0
S = {x ∈ R / x' = 7.0, x" = 2.0 }