5x2 +13x +6 = 0
ax2 bx c = 0
a = 5
b = 13
c = 6
Δ = b2-4ac
Δ = 13² - (4 * 5 * 6)
Δ = 169 - (4*30)
Δ = 169 - (120)
Δ = 49 Δ > 0
5x2+13x+6=0
x = -b ∓ √Δ 2a
x' = -13 - √49 2*5 = -13 - 7.0 10 = -20.0 10 = -2.0
x" = -13 + √49 2*5 = -13 + 7.0 10 = -6.0 10 = -0.6
x' = -50.0
x" = -15.0
S = {x ∈ R / x' = -50.0, x" = -15.0 }