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 = 49 Δ > 0
5x2+17x+12=0
x = -b ∓ √Δ 2a
x' = -17 - √49 2*5 = -17 - 7.0 10 = -24.0 10 = -2.4
x" = -17 + √49 2*5 = -17 + 7.0 10 = -10.0 10 = -1.0
x' = -60.0
x" = -25.0
S = {x ∈ R / x' = -60.0, x" = -25.0 }