-4x2 +14x +8 = 0
ax2 bx c = 0
a = -4
b = 14
c = 8
Δ = b2-4ac
Δ = 14² - (4 * -4 * 8)
Δ = 196 - (4*-32)
Δ = 196 - (-128)
Δ = 324 Δ > 0
-4x2+14x+8=0
x = -b ∓ √Δ 2a
x' = -14 - √324 2*-4 = -14 - 18.0 -8 = -32.0 -8 = 4.0
x" = -14 + √324 2*-4 = -14 + 18.0 -8 = 4.0 -8 = -0.5
x' = 64.0
x" = -8.0
S = {x ∈ R / x' = 64.0, x" = -8.0 }