| ( | 180 | − | 100 | ) | ÷ | ( | 200 | − | 100 | ) | = | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) |
| 方程两边同时乘以: | ( | 200 | − | 100 | ) | , | ( | 7000 | − | 5000 | ) |
| ( | 180 | − | 100 | ) | ( | 7000 | − | 5000 | ) | = | ( | x | − | 5000 | ) | ( | 200 | − | 100 | ) |
| 180 | ( | 7000 | − | 5000 | ) | − | 100 | ( | 7000 | − | 5000 | ) | = | ( | x | − | 5000 | ) | ( | 200 | − | 100 | ) |
| 180 | ( | 7000 | − | 5000 | ) | − | 100 | ( | 7000 | − | 5000 | ) | = | x | ( | 200 | − | 100 | ) | − | 5000 | ( | 200 | − | 100 | ) |
| 180 | × | 7000 | − | 180 | × | 5000 | − | 100 | ( | 7000 | − | 5000 | ) | = | x | ( | 200 | − | 100 | ) | − | 5000 | ( | 200 | − | 100 | ) |
| 180 | × | 7000 | − | 180 | × | 5000 | − | 100 | ( | 7000 | − | 5000 | ) | = | x | × | 200 | − | x | × | 100 | − | 5000 | ( | 200 | − | 100 | ) |
| 1260000 | − | 900000 | − | 100 | ( | 7000 | − | 5000 | ) | = | x | × | 200 | − | x | × | 100 | − | 5000 | ( | 200 | − | 100 | ) |
| 360000 | − | 100 | ( | 7000 | − | 5000 | ) | = | 100 | x | − | 5000 | ( | 200 | − | 100 | ) |
| 360000 | − | 100 | × | 7000 | + | 100 | × | 5000 | = | 100 | x | − | 5000 | ( | 200 | − | 100 | ) |
| 360000 | − | 100 | × | 7000 | + | 100 | × | 5000 | = | 100 | x | − | 5000 | × | 200 | + | 5000 | × | 100 |
| 360000 | − | 700000 | + | 500000 | = | 100 | x | − | 1000000 | + | 500000 |
| 160000 | = | 100 | x | − | 500000 |
| - | 100 | x | = | - | 500000 | − | 160000 |
| - | 100 | x | = | - | 660000 |
| 660000 | = | 100 | x |
| 100 | x | = | 660000 |
| x | = | 660000 | ÷ | 100 |
| = | 660000 | × | 1 100 |
| = | 6600 | × | 1 |
| x | = | 6600 |