-15x2 +23x +14 = 0
ax2 bx c = 0
a = -15
b = 23
c = 14
Δ = b2-4ac
Δ = 23² - (4 * -15 * 14)
Δ = 529 - (4*-210)
Δ = 529 - (-840)
Δ = 1369 Δ > 0
-15x2+23x+14=0
x = -b ∓ √Δ 2a
x' = -23 - √1369 2*-15 = -23 - 37.0 -30 = -60.0 -30 = 2.0
x" = -23 + √1369 2*-15 = -23 + 37.0 -30 = 14.0 -30 = -0.466666666667
x' = 450.0
x" = -105.0
S = {x ∈ R / x' = 450.0, x" = -105.0 }