-1x2 -7x -6 = 0
ax2 bx c = 0
a = -1
b = -7
c = -6
Δ = b2-4ac
Δ = -7² - (4 * -1 * -6)
Δ = 49 - (4*6)
Δ = 49 - (24)
Δ = 25 Δ > 0
-x2-7x-6=0
x = -b ∓ √Δ 2a
x' = 7 - √25 2*-1 = 7 - 5.0 -2 = 2.0 -2 = -1.0
x" = 7 + √25 2*-1 = 7 + 5.0 -2 = 12.0 -2 = -6.0
x' = -1.0
x" = -6.0
S = {x ∈ R / x' = -1.0, x" = -6.0 }