-12x2 +11x +15 = 0
ax2 bx c = 0
a = -12
b = 11
c = 15
Δ = b2-4ac
Δ = 11² - (4 * -12 * 15)
Δ = 121 - (4*-180)
Δ = 121 - (-720)
Δ = 841 Δ > 0
-12x2+11x+15=0
x = -b ∓ √Δ 2a
x' = -11 - √841 2*-12 = -11 - 29.0 -24 = -40.0 -24 = 1.66666666667
x" = -11 + √841 2*-12 = -11 + 29.0 -24 = 18.0 -24 = -0.75
x' = 240.0
x" = -108.0
S = {x ∈ R / x' = 240.0, x" = -108.0 }