The problem states:

"Brojevi x, x - 2, y - 2, 2y - x četiri su uzastopna člana aritmetičkog niza. Koji realni brojevi su članovi niza?"

Translation: The numbers $x, x-2, y-2, 2y-x$ are four consecutive terms of an arithmetic sequence. Find the real numbers that are members of the sequence.

Step-by-step Solution:

In an arithmetic sequence, the difference between consecutive terms is constant. Let $d$ be the common difference.

From the given terms:

1. $x$
2. $x-2$
3. $y-2$
4. $2y-x$

The common difference $d$ can be expressed between any two consecutive terms:

1. From the first and second terms: $(x - 2) - x = d \implies d = -2$

2. From the second and third terms: $(y - 2) - (x - 2) = d$ Simplify: $y - 2 - x + 2 = d \implies y - x = d$ Since $d = -2$, we get: $y - x = -2 \implies y = x - 2$

3. From the third and fourth terms: $(2y - x) - (y - 2) = d$ Substitute $y = x - 2$: $(2(x - 2) - x) - ((x - 2) - 2) = d$ Simplify step-by-step: $(2x - 4 - x) - (x - 2 - 2) = d$ $(x - 4) - (x - 4) = d$ $0 = d$