| ( | ( | X | − | 400 | − | 160 | ) | × | 3 4 | − | 100 | ) | ÷ | 1000 | = | ( | ( | X | − | 400 | ) | × | 3 4 | − | 100 | ) | ÷ | 1200 |
| 方程左边 = | ( | X | − | 400 | − | 160 | ) | × | 3 4 | × | 1 1000 | − | 100 | × | 1 1000 |
| = | ( | X | − | 400 | − | 160 | ) | × | 3 4000 | − | 1 10 |
| = | X | × | 3 4000 | − | 400 | × | 3 4000 | − | 160 | × | 3 4000 | − | 1 10 |
| = | X | × | 3 4000 | − | 3 10 | − | 3 25 | − | 1 10 |
| = | 3 4000 | X | − | 13 25 |
3 4000 | X | − | 13 25 | = | ( | ( | X | − | 400 | ) | × | 3 4 | − | 100 | ) | ÷ | 1200 |
| 方程右边 = | ( | X | − | 400 | ) | × | 3 4 | × | 1 1200 | − | 100 | × | 1 1200 |
| = | ( | X | − | 400 | ) | × | 1 1600 | − | 1 12 |
| = | X | × | 1 1600 | − | 400 | × | 1 1600 | − | 1 12 |
| = | X | × | 1 1600 | − | 1 4 | − | 1 12 |
| = | 1 1600 | X | − | 1 3 |
3 4000 | X | − | 13 25 | = | 1 1600 | X | − | 1 3 |
3 4000 | X | − | 1 1600 | X | = | - | 1 3 | + | 13 25 |
1 8000 | X | = | - | 1 3 | + | 13 25 |
1 8000 | X | = | 14 75 |
| X | = | 14 75 | ÷ | 1 8000 |
| = | 14 75 | × | 8000 |
| = | 14 3 | × | 320 |
| X | = | 4480 3 |
| X | = | 1493.333333 |