-6x2 -7x +20 = 0
ax2 bx c = 0
a = -6
b = -7
c = 20
Δ = b2-4ac
Δ = -7² - (4 * -6 * 20)
Δ = 49 - (4*-120)
Δ = 49 - (-480)
Δ = 529 Δ > 0
-6x2-7x+20=0
x = -b ∓ √Δ 2a
x' = 7 - √529 2*-6 = 7 - 23.0 -12 = -16.0 -12 = 1.33333333333
x" = 7 + √529 2*-6 = 7 + 23.0 -12 = 30.0 -12 = -2.5
x' = 48.0
x" = -90.0
S = {x ∈ R / x' = 48.0, x" = -90.0 }