-6x2 +23x -20 = 0
ax2 bx c = 0
a = -6
b = 23
c = -20
Δ = b2-4ac
Δ = 23² - (4 * -6 * -20)
Δ = 529 - (4*120)
Δ = 529 - (480)
Δ = 49 Δ > 0
-6x2+23x-20=0
x = -b ∓ √Δ 2a
x' = -23 - √49 2*-6 = -23 - 7.0 -12 = -30.0 -12 = 2.5
x" = -23 + √49 2*-6 = -23 + 7.0 -12 = -16.0 -12 = 1.33333333333
x' = 90.0
x" = 48.0
S = {x ∈ R / x' = 90.0, x" = 48.0 }