15x2 -13x +2 = 0
ax2 bx c = 0
a = 15
b = -13
c = 2
Δ = b2-4ac
Δ = -13² - (4 * 15 * 2)
Δ = 169 - (4*30)
Δ = 169 - (120)
Δ = 49 Δ > 0
15x2-13x+2=0
x = -b ∓ √Δ 2a
x' = 13 - √49 2*15 = 13 - 7.0 30 = 6.0 30 = 0.2
x" = 13 + √49 2*15 = 13 + 7.0 30 = 20.0 30 = 0.666666666667
x' = 45.0
x" = 150.0
S = {x ∈ R / x' = 45.0, x" = 150.0 }