-1x2 -7x -10 = 0
ax2 bx c = 0
a = -1
b = -7
c = -10
Δ = b2-4ac
Δ = -7² - (4 * -1 * -10)
Δ = 49 - (4*10)
Δ = 49 - (40)
Δ = 9 Δ > 0
-x2-7x-10=0
x = -b ∓ √Δ 2a
x' = 7 - √9 2*-1 = 7 - 3.0 -2 = 4.0 -2 = -2.0
x" = 7 + √9 2*-1 = 7 + 3.0 -2 = 10.0 -2 = -5.0
x' = -2.0
x" = -5.0
S = {x ∈ R / x' = -2.0, x" = -5.0 }