-12x2 -x +20 = 0
ax2 bx c = 0
a = -12
b = -1
c = 20
Δ = b2-4ac
Δ = -² - (4 * -12 * 20)
Δ = 1 - (4*-240)
Δ = 1 - (-960)
Δ = 961 Δ > 0
-12x2-x+20=0
x = -b ∓ √Δ 2a
x' = 1 - √961 2*-12 = 1 - 31.0 -24 = -30.0 -24 = 1.25
x" = 1 + √961 2*-12 = 1 + 31.0 -24 = 32.0 -24 = -1.33333333333
x' = 180.0
x" = -192.0
S = {x ∈ R / x' = 180.0, x" = -192.0 }