5x2 -17x -12 = 0
ax2 bx c = 0
a = 5
b = -17
c = -12
Δ = b2-4ac
Δ = -17² - (4 * 5 * -12)
Δ = 289 - (4*-60)
Δ = 289 - (-240)
Δ = 529 Δ > 0
5x2-17x-12=0
x = -b ∓ √Δ 2a
x' = 17 - √529 2*5 = 17 - 23.0 10 = -6.0 10 = -0.6
x" = 17 + √529 2*5 = 17 + 23.0 10 = 40.0 10 = 4.0
x' = -15.0
x" = 100.0
S = {x ∈ R / x' = -15.0, x" = 100.0 }