5x2 +19x +14 = 0
ax2 bx c = 0
a = 5
b = 19
c = 14
Δ = b2-4ac
Δ = 19² - (4 * 5 * 14)
Δ = 361 - (4*70)
Δ = 361 - (280)
Δ = 81 Δ > 0
5x2+19x+14=0
x = -b ∓ √Δ 2a
x' = -19 - √81 2*5 = -19 - 9.0 10 = -28.0 10 = -2.8
x" = -19 + √81 2*5 = -19 + 9.0 10 = -10.0 10 = -1.0
x' = -70.0
x" = -25.0
S = {x ∈ R / x' = -70.0, x" = -25.0 }