5x2 -15x +10 = 0
ax2 bx c = 0
a = 5
b = -15
c = 10
Δ = b2-4ac
Δ = -15² - (4 * 5 * 10)
Δ = 225 - (4*50)
Δ = 225 - (200)
Δ = 25 Δ > 0
5x2-15x+10=0
x = -b ∓ √Δ 2a
x' = 15 - √25 2*5 = 15 - 5.0 10 = 10.0 10 = 1.0
x" = 15 + √25 2*5 = 15 + 5.0 10 = 20.0 10 = 2.0
x' = 25.0
x" = 50.0
S = {x ∈ R / x' = 25.0, x" = 50.0 }