| 1000 | ÷ | X | × | 2 | + | 1000 | ÷ | X | × | 4 | + | 3000 | ÷ | X | × | 3 | − | 3000 | = | 0 |
| 方程两边同时乘以: | X |
| 1000 | × | 2 | + | 1000 | ÷ | 1 | × | 4 | × | 1 | + | 3000 | ÷ | 1 | × | 3 | × | 1 | − | 3000 | X | = | 0 |
| - | 3000 | X | = | 0 | − | 1000 | × | 2 | − | 1000 | ÷ | 1 | × | 4 | × | 1 | − | 3000 | ÷ | 1 | × | 3 | × | 1 |
| - | 3000 | X | = | 0 | − | 2000 | − | 4000 | − | 9000 |
| - | 3000 | X | = | - | 15000 |
| 15000 | = | 3000 | X |
| 3000 | X | = | 15000 |
| X | = | 15000 | ÷ | 3000 |
| = | 15000 | × | 1 3000 |
| = | 5 | × | 1 |
| X | = | 5 |