-7x2 -6x +1 = 0
ax2 bx c = 0
a = -7
b = -6
c = 1
Δ = b2-4ac
Δ = -6² - (4 * -7 * 1)
Δ = 36 - (4*-7)
Δ = 36 - (-28)
Δ = 64 Δ > 0
-7x2-6x+1=0
x = -b ∓ √Δ 2a
x' = 6 - √64 2*-7 = 6 - 8.0 -14 = -2.0 -14 = 0.142857142857
x" = 6 + √64 2*-7 = 6 + 8.0 -14 = 14.0 -14 = -1.0
x' = 7.0
x" = -49.0
S = {x ∈ R / x' = 7.0, x" = -49.0 }