-4x2 -9x +9 = 0
ax2 bx c = 0
a = -4
b = -9
c = 9
Δ = b2-4ac
Δ = -9² - (4 * -4 * 9)
Δ = 81 - (4*-36)
Δ = 81 - (-144)
Δ = 225 Δ > 0
-4x2-9x+9=0
x = -b ∓ √Δ 2a
x' = 9 - √225 2*-4 = 9 - 15.0 -8 = -6.0 -8 = 0.75
x" = 9 + √225 2*-4 = 9 + 15.0 -8 = 24.0 -8 = -3.0
x' = 12.0
x" = -48.0
S = {x ∈ R / x' = 12.0, x" = -48.0 }