| 150 | ( | 100 | − | ( | X | − | 3000 | ÷ | 50 | ) | ) | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 | = | 0 |
| 方程左边 = | 150 | × | 100 | − | 150 | ( | X | − | 3000 | ÷ | 50 | ) | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 |
| = | 15000 | − | 150 | ( | X | − | 3000 | ÷ | 50 | ) | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 |
| = | 15000 | − | 150 | X | + | 150 | × | 3000 | ÷ | 50 | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 |
| = | 15000 | − | 150 | X | + | 9000 | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 |
| = | 24000 | − | 150 | X | − | ( | X | − | 3000 | ÷ | 50 | ) | × | 50 |
| = | 24000 | − | 150 | X | − | X | × | 50 | + | 3000 | ÷ | 50 | × | 50 |
| = | 24000 | − | 150 | X | − | X | × | 50 | + | 3000 |
| = | 27000 | − | 200 | X |
| 27000 | − | 200 | X | = | 0 |
| - | 200 | X | = | 0 | − | 27000 |
| - | 200 | X | = | - | 27000 |
| 27000 | = | 200 | X |
| 200 | X | = | 27000 |
| X | = | 27000 | ÷ | 200 |
| = | 27000 | × | 1 200 |
| = | 135 | × | 1 |
| X | = | 135 |