15x2 +19x +6 = 0
ax2 bx c = 0
a = 15
b = 19
c = 6
Δ = b2-4ac
Δ = 19² - (4 * 15 * 6)
Δ = 361 - (4*90)
Δ = 361 - (360)
Δ = 1 Δ > 0
15x2+19x+6=0
x = -b ∓ √Δ 2a
x' = -19 - √1 2*15 = -19 - 1.0 30 = -20.0 30 = -0.666666666667
x" = -19 + √1 2*15 = -19 + 1.0 30 = -18.0 30 = -0.6
x' = -150.0
x" = -135.0
S = {x ∈ R / x' = -150.0, x" = -135.0 }