-9x2 -14x -5 = 0
ax2 bx c = 0
a = -9
b = -14
c = -5
Δ = b2-4ac
Δ = -14² - (4 * -9 * -5)
Δ = 196 - (4*45)
Δ = 196 - (180)
Δ = 16 Δ > 0
-9x2-14x-5=0
x = -b ∓ √Δ 2a
x' = 14 - √16 2*-9 = 14 - 4.0 -18 = 10.0 -18 = -0.555555555556
x" = 14 + √16 2*-9 = 14 + 4.0 -18 = 18.0 -18 = -1.0
x' = -45.0
x" = -81.0
S = {x ∈ R / x' = -45.0, x" = -81.0 }