-12x2 -8x +15 = 0
ax2 bx c = 0
a = -12
b = -8
c = 15
Δ = b2-4ac
Δ = -8² - (4 * -12 * 15)
Δ = 64 - (4*-180)
Δ = 64 - (-720)
Δ = 784 Δ > 0
-12x2-8x+15=0
x = -b ∓ √Δ 2a
x' = 8 - √784 2*-12 = 8 - 28.0 -24 = -20.0 -24 = 0.833333333333
x" = 8 + √784 2*-12 = 8 + 28.0 -24 = 36.0 -24 = -1.5
x' = 120.0
x" = -216.0
S = {x ∈ R / x' = 120.0, x" = -216.0 }