15x2 -11x -12 = 0
ax2 bx c = 0
a = 15
b = -11
c = -12
Δ = b2-4ac
Δ = -11² - (4 * 15 * -12)
Δ = 121 - (4*-180)
Δ = 121 - (-720)
Δ = 841 Δ > 0
15x2-11x-12=0
x = -b ∓ √Δ 2a
x' = 11 - √841 2*15 = 11 - 29.0 30 = -18.0 30 = -0.6
x" = 11 + √841 2*15 = 11 + 29.0 30 = 40.0 30 = 1.33333333333
x' = -135.0
x" = 300.0
S = {x ∈ R / x' = -135.0, x" = 300.0 }