5x2 -2x -3 = 0
ax2 bx c = 0
a = 5
b = -2
c = -3
Δ = b2-4ac
Δ = -2² - (4 * 5 * -3)
Δ = 4 - (4*-15)
Δ = 4 - (-60)
Δ = 64 Δ > 0
5x2-2x-3=0
x = -b ∓ √Δ 2a
x' = 2 - √64 2*5 = 2 - 8.0 10 = -6.0 10 = -0.6
x" = 2 + √64 2*5 = 2 + 8.0 10 = 10.0 10 = 1.0
x' = -15.0
x" = 25.0
S = {x ∈ R / x' = -15.0, x" = 25.0 }