-9x2 -13x +10 = 0
ax2 bx c = 0
a = -9
b = -13
c = 10
Δ = b2-4ac
Δ = -13² - (4 * -9 * 10)
Δ = 169 - (4*-90)
Δ = 169 - (-360)
Δ = 529 Δ > 0
-9x2-13x+10=0
x = -b ∓ √Δ 2a
x' = 13 - √529 2*-9 = 13 - 23.0 -18 = -10.0 -18 = 0.555555555556
x" = 13 + √529 2*-9 = 13 + 23.0 -18 = 36.0 -18 = -2.0
x' = 45.0
x" = -162.0
S = {x ∈ R / x' = 45.0, x" = -162.0 }