If `(30-x)^@` is supplement of `(125+2x)^@` then x is ___

Answer

To solve the problem, we need to find the value of \( x \) given that \( (30 - x)^\circ \) is the supplement of \( (125 + 2x)^\circ \).

### Step-by-step Solution:

1. **Understanding Supplementary Angles**:
- Two angles are supplementary if their sum is \( 180^\circ \).
- Therefore, we can write the equation:
\[ (30 - x) + (125 + 2x) = 180 \]

2. **Combine Like Terms**:
- Simplify the left side of the equation:
\[ 30 - x + 125 + 2x = 180 \]
- Combine the constants and the \( x \) terms:
\[ (30 + 125) + (-x + 2x) = 180 \]
\[ 155 + x = 180 \]

3. **Isolate \( x \)**:
- Subtract \( 155 \) from both sides:
\[ x = 180 - 155 \]
\[ x = 25 \]

4. **Conclusion**:
- The value of \( x \) is \( 25 \).

### Final Answer:
Thus, \( x \) is \( 25 \).