a = 2 (slider from -5 to 5, step 0.1)
b = 3 (slider from -5 to 5, step 0.1)
m = 0 (slider from -5 to 5, step 0.1)
n = 4 (slider from -5 to 5, step 0.1)
f(x) = (a * x - m) / (b * x - n)
as_s = Asymptote(f)
S: (n / b, a / b)
g = PartialFractions(f)
A = Root(f, -1, 1)