[ - 4 , 4 ) ∪ ( 4 , ∞ )
The denominator of f(x) cannot be zero as this would make f(x) undefined. Equating the denominator to zero and solving gives the value that x cannot be.
solve x - 4 = 0 ⇒ x = 4 ( is a vertical asymptote )
There is a zero when the numerator equals zero.
x + 4 = 0 ⇒ x = - 4 ( is a zero )
domain is [-4 , 4 ) ∪ ( 4 , ∞ )
