63:124-X:3)=7

Решение:

1. \[ 63:(24-x):3=7 \]
2. \[ (24-x):3 = 63:7 \]
3. \[ (24-x):3 = 9 \]
4. \[ 24-x = 9 \cdot 3 \]
5. \[ 24-x = 27 \]
6. \[ x = 24 - 27 \]
7. \[ x = -3 \]

Ответ: x = -3