Perform the subtraction.

(4x/x^2+2x-8)-(x/x^2-16)

To perform the subtraction of the given expressions:

1. First, factorize the denominators of both fractions to simplify the expression.

For the first fraction, x^2 + 2x - 8, it can be factored as (x+4)(x-2).

For the second fraction, x^2 - 16, it can be factored as (x+4)(x-4).

2. Rewrite the expression using the factored denominators:

(4x/(x+4)(x-2)) - (x/(x+4)(x-4))

3. Since the denominators are now the same, we can combine the numerators:

[(4x - x)/(x+4)(x-2)]

4. Simplify the numerator:

(3x)/(x+4)(x-2)

Therefore, the final result of the subtraction is 3x/(x+4)(x-2).