-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 = -4.0 -8 = 0.5
x" = 14 + √324 2*-4 = 14 + 18.0 -8 = 32.0 -8 = -4.0
x' = 8.0
x" = -64.0
S = {x ∈ R / x' = 8.0, x" = -64.0 }