-9x2 +11x +14 = 0
ax2 bx c = 0
a = -9
b = 11
c = 14
Δ = b2-4ac
Δ = 11² - (4 * -9 * 14)
Δ = 121 - (4*-126)
Δ = 121 - (-504)
Δ = 625 Δ > 0
-9x2+11x+14=0
x = -b ∓ √Δ 2a
x' = -11 - √625 2*-9 = -11 - 25.0 -18 = -36.0 -18 = 2.0
x" = -11 + √625 2*-9 = -11 + 25.0 -18 = 14.0 -18 = -0.777777777778
x' = 162.0
x" = -63.0
S = {x ∈ R / x' = 162.0, x" = -63.0 }