To simplify the expression 1/x - 2a + 1/x + 2a + 8a^2 / 4a^2 - x^3, we need to combine like terms and look for common factors in the terms.

1/x + 1/x can be combined to give 2/x.

-2a + 2a cancel each other out when combined.

Next, we can simplify 8a^2 / 4a^2 to 2.

So our simplified expression becomes:

2/x + 2

Now, let's tackle the last term 4a^2 - x^3. This cannot be further simplified without additional information about the values of a and x.

Therefore, the final simplified expression is:

2/x + 2 + 4a^2 - x^3