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 = 10.0 10 = 1.0
x" = 19 + √81 2*5 = 19 + 9.0 10 = 28.0 10 = 2.8
x' = 25.0
x" = 70.0
S = {x ∈ R / x' = 25.0, x" = 70.0 }