Question

What are the holes of the function f(x) = (x^2 + 3x - 4)/(x^2 + 9x + 20)?

Answer 1

That will be where the numerator and denominator are both zero.

x^2+3x-4 = (x+4)(x-1)
x^2+9x+20 = (x+4)(x+5)

so, ...