| 1000 | ( | 112 100 | − | 36 100 | ) | − | 6000 | × | 8 100 | ( | 1 | − | X | ) | = | 664 |
| 方程左边 = | 1000 | ( | 112 100 | − | 36 100 | ) | − | 480 | ( | 1 | − | X | ) |
| 1000 | ( | 112 100 | − | 36 100 | ) | − | 480 | ( | 1 | − | X | ) | = | 664 |
| 方程左边 = | 1000 | × | 112 100 | − | 1000 | × | 36 100 | − | 480 | ( | 1 | − | X | ) |
| = | 1120 | − | 360 | − | 480 | ( | 1 | − | X | ) |
| = | 760 | − | 480 | ( | 1 | − | X | ) |
| = | 760 | − | 480 | × | 1 | + | 480 | X |
| = | 760 | − | 480 | + | 480 | X |
| = | 280 | + | 480 | X |
| 280 | + | 480 | X | = | 664 |
| 480 | X | = | 664 | − | 280 |
| 480 | X | = | 384 |
| X | = | 384 | ÷ | 480 |
| = | 384 | × | 1 480 |
| = | 4 | × | 1 5 |
| X | = | 4 5 |
| X | = | 0.8 |