-6x2 +19x -15 = 0
ax2 bx c = 0
a = -6
b = 19
c = -15
Δ = b2-4ac
Δ = 19² - (4 * -6 * -15)
Δ = 361 - (4*90)
Δ = 361 - (360)
Δ = 1 Δ > 0
-6x2+19x-15=0
x = -b ∓ √Δ 2a
x' = -19 - √1 2*-6 = -19 - 1.0 -12 = -20.0 -12 = 1.66666666667
x" = -19 + √1 2*-6 = -19 + 1.0 -12 = -18.0 -12 = 1.5
x' = 60.0
x" = 54.0
S = {x ∈ R / x' = 60.0, x" = 54.0 }