-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 = -30.0 -30 = 1.0
x" = 1 + √961 2*-15 = 1 + 31.0 -30 = 32.0 -30 = -1.06666666667
x' = 225.0
x" = -240.0
S = {x ∈ R / x' = 225.0, x" = -240.0 }