| 210 | ( | 10 | − | x | ) | − | 450 | − | 150 | = | 570 |
| 方程左边 = | 210 | ( | 10 | − | x | ) | − | 600 |
| 210 | ( | 10 | − | x | ) | − | 600 | = | 570 |
| 方程左边 = | 210 | × | 10 | − | 210 | x | − | 600 |
| = | 2100 | − | 210 | x | − | 600 |
| = | 1500 | − | 210 | x |
| 1500 | − | 210 | x | = | 570 |
| - | 210 | x | = | 570 | − | 1500 |
| - | 210 | x | = | - | 930 |
| 930 | = | 210 | x |
| 210 | x | = | 930 |
| x | = | 930 | ÷ | 210 |
| = | 930 | × | 1 210 |
| = | 31 | × | 1 7 |
| x | = | 31 7 |
| x | = | 4.428571 |