OK, the problem i have here i can't even begin to solve, so im in need of some help. Here's the exact problem:

If the following conditions are true

1. f '(x) = f(x) - g(x) [the apostrophe means the derivitive of f of x]

2. g '(x) = g(x) - f(x)

3. f(0) = 5

4. g(0) = 1

5. f and g are continuous are differentiable functions

Find the constant value of f(x) + g(x) for all x. Explain your work and your steps.

There it is. I don't get it at all, but my math teacher thinks i should for whatever reason. Please help! Thanks in advance!