To solve the equation \( x + (-2) = x - 2 \), we can simplify both sides.
The left side simplifies to: \[ x - 2 \]
So we have: \[ x - 2 = x - 2 \]
Since both sides are equal for any value of \( x \), the equation is true for all values of \( x \). Therefore, there is no unique solution; any number will satisfy the equation.