5x2 -8x +3 = 0
ax2 bx c = 0
a = 5
b = -8
c = 3
Δ = b2-4ac
Δ = -8² - (4 * 5 * 3)
Δ = 64 - (4*15)
Δ = 64 - (60)
Δ = 4 Δ > 0
5x2-8x+3=0
x = -b ∓ √Δ 2a
x' = 8 - √4 2*5 = 8 - 2.0 10 = 6.0 10 = 0.6
x" = 8 + √4 2*5 = 8 + 2.0 10 = 10.0 10 = 1.0
x' = 15.0
x" = 25.0
S = {x ∈ R / x' = 15.0, x" = 25.0 }