-6x2 +11x +7 = 0
ax2 bx c = 0
a = -6
b = 11
c = 7
Δ = b2-4ac
Δ = 11² - (4 * -6 * 7)
Δ = 121 - (4*-42)
Δ = 121 - (-168)
Δ = 289 Δ > 0
-6x2+11x+7=0
x = -b ∓ √Δ 2a
x' = -11 - √289 2*-6 = -11 - 17.0 -12 = -28.0 -12 = 2.33333333333
x" = -11 + √289 2*-6 = -11 + 17.0 -12 = 6.0 -12 = -0.5
x' = 84.0
x" = -18.0
S = {x ∈ R / x' = 84.0, x" = -18.0 }