-6x2 -13x +5 = 0
ax2 bx c = 0
a = -6
b = -13
c = 5
Δ = b2-4ac
Δ = -13² - (4 * -6 * 5)
Δ = 169 - (4*-30)
Δ = 169 - (-120)
Δ = 289 Δ > 0
-6x2-13x+5=0
x = -b ∓ √Δ 2a
x' = 13 - √289 2*-6 = 13 - 17.0 -12 = -4.0 -12 = 0.333333333333
x" = 13 + √289 2*-6 = 13 + 17.0 -12 = 30.0 -12 = -2.5
x' = 12.0
x" = -90.0
S = {x ∈ R / x' = 12.0, x" = -90.0 }