To simplify the expression, we can combine like terms:

2a - 2c + ax - cx / x^2 - 4

Rearranging the terms:

(a + ax - 2c - cx) / (x^2 - 4)

Factor out common terms:

a(1 + x) - 2c(1 + x) / (x^2 - 4)

Factor the denominator:

a(1 + x) - 2c(1 + x) / (x - 2)(x + 2)

Factor out the common factor of (1 + x):

(1 + x)(a - 2c) / (x - 2)(x + 2)

So, 2a - 2c + ax - cx / x^2 - 4 simplifies to (1 + x)(a - 2c) / (x - 2)(x + 2)