-4x2 +10x +14 = 0

ax2 bx c = 0

a = -4

b = 10

c = 14

Δ = b2-4ac

Δ = 10² - (4 * -4 * 14)

Δ = 100 - (4*-56)

Δ = 100 - (-224)

Δ = 324      Δ > 0

-4x2+10x+14=0

x = -b ∓ √Δ 2a

x' = -10 - √324 2*-4 = -10 - 18.0 -8 = -28.0 -8 = 3.5

x" = -10 + √324 2*-4 = -10 + 18.0 -8 = 8.0 -8 = -1.0

x' = 56.0

x" = -16.0

S = {x ∈ R / x' = 56.0, x" = -16.0 }