How many real numbers are not in the domain of the function

f(x)=(1/x-64)+(1/x^2-64)+(1/x^3-64)? Thank you!

well, where are the denominators zero?

x-64 = 0
x^2-64 = (x-8)(x+8) = 0
x^3-64 = (x-4)(x^2+4x+16) = 0