5x2 +4x -12 = 0
ax2 bx c = 0
a = 5
b = 4
c = -12
Δ = b2-4ac
Δ = 4² - (4 * 5 * -12)
Δ = 16 - (4*-60)
Δ = 16 - (-240)
Δ = 256 Δ > 0
5x2+4x-12=0
x = -b ∓ √Δ 2a
x' = -4 - √256 2*5 = -4 - 16.0 10 = -20.0 10 = -2.0
x" = -4 + √256 2*5 = -4 + 16.0 10 = 12.0 10 = 1.2
x' = -50.0
x" = 30.0
S = {x ∈ R / x' = -50.0, x" = 30.0 }