15x2 +x -16 = 0
ax2 bx c = 0
a = 15
b = 1
c = -16
Δ = b2-4ac
Δ = ² - (4 * 15 * -16)
Δ = 1 - (4*-240)
Δ = 1 - (-960)
Δ = 961 Δ > 0
15x2+x-16=0
x = -b ∓ √Δ 2a
x' = -1 - √961 2*15 = -1 - 31.0 30 = -32.0 30 = -1.06666666667
x" = -1 + √961 2*15 = -1 + 31.0 30 = 30.0 30 = 1.0
x' = -240.0
x" = 225.0
S = {x ∈ R / x' = -240.0, x" = 225.0 }