Question

find the implied domain? f(x)= cubedradical(4x-6)/(x^2+16)

Answer 1

You need to find where there would be problems with the equation for certain x-values. These happen when a square root is negative or a denominator is 0. In this case you don't have a square root so look at the denominator:
x^2 + 16 = 0
This will only happen in the complex plane (±4i) so there are no issues with the domain.
x = all reals