-9x2 -10x +16 = 0
ax2 bx c = 0
a = -9
b = -10
c = 16
Δ = b2-4ac
Δ = -10² - (4 * -9 * 16)
Δ = 100 - (4*-144)
Δ = 100 - (-576)
Δ = 676 Δ > 0
-9x2-10x+16=0
x = -b ∓ √Δ 2a
x' = 10 - √676 2*-9 = 10 - 26.0 -18 = -16.0 -18 = 0.888888888889
x" = 10 + √676 2*-9 = 10 + 26.0 -18 = 36.0 -18 = -2.0
x' = 72.0
x" = -162.0
S = {x ∈ R / x' = 72.0, x" = -162.0 }