15x2 +23x +6 = 0
ax2 bx c = 0
a = 15
b = 23
c = 6
Δ = b2-4ac
Δ = 23² - (4 * 15 * 6)
Δ = 529 - (4*90)
Δ = 529 - (360)
Δ = 169 Δ > 0
15x2+23x+6=0
x = -b ∓ √Δ 2a
x' = -23 - √169 2*15 = -23 - 13.0 30 = -36.0 30 = -1.2
x" = -23 + √169 2*15 = -23 + 13.0 30 = -10.0 30 = -0.333333333333
x' = -270.0
x" = -75.0
S = {x ∈ R / x' = -270.0, x" = -75.0 }