-6x2 +19x -13 = 0
ax2 bx c = 0
a = -6
b = 19
c = -13
Δ = b2-4ac
Δ = 19² - (4 * -6 * -13)
Δ = 361 - (4*78)
Δ = 361 - (312)
Δ = 49 Δ > 0
-6x2+19x-13=0
x = -b ∓ √Δ 2a
x' = -19 - √49 2*-6 = -19 - 7.0 -12 = -26.0 -12 = 2.16666666667
x" = -19 + √49 2*-6 = -19 + 7.0 -12 = -12.0 -12 = 1.0
x' = 78.0
x" = 36.0
S = {x ∈ R / x' = 78.0, x" = 36.0 }