381 = 123

This appears to be an incomplete equation. However, based on the provided numbers, it is presented as \( 381 = 123 \), which is mathematically incorrect. If this were intended as a subtraction problem \( 381 - X = 123 \), then \( X = 381 - 123 = 258 \). If it were an addition problem \( X + 381 = 123 \), then \( X = 123 - 381 = -258 \). Without further context, the given statement is false.

Ответ: The equation as presented is incorrect.