-6x2 -17x -7 = 0
ax2 bx c = 0
a = -6
b = -17
c = -7
Δ = b2-4ac
Δ = -17² - (4 * -6 * -7)
Δ = 289 - (4*42)
Δ = 289 - (168)
Δ = 121 Δ > 0
-6x2-17x-7=0
x = -b ∓ √Δ 2a
x' = 17 - √121 2*-6 = 17 - 11.0 -12 = 6.0 -12 = -0.5
x" = 17 + √121 2*-6 = 17 + 11.0 -12 = 28.0 -12 = -2.33333333333
x' = -18.0
x" = -84.0
S = {x ∈ R / x' = -18.0, x" = -84.0 }