| ( | 17000 | × | 12 | − | 7 10 | × | 180 | X | × | 637 10000 | ) | ÷ | ( | 7 20 | × | 180 | X | ) | = | 19 500 |
| 方程两边同时乘以: | ( | 7 20 | × | 180 | X | ) |
| ( | 17000 | × | 12 | − | 7 10 | × | 180 | X | × | 637 10000 | ) | = | 19 500 | ( | 7 20 | × | 180 | X | ) |
| 17000 | × | 12 | − | 7 10 | × | 180 | X | × | 637 10000 | = | 19 500 | ( | 7 20 | × | 180 | X | ) |
| 17000 | × | 12 | − | 7 10 | × | 180 | X | × | 637 10000 | = | 19 500 | × | 7 20 | × | 180 | X |
| 204000 | − | 40131 5000 | X | = | 1197 500 | X |
| - | 40131 5000 | X | − | 1197 500 | X | = | - | 204000 |
| - | 52101 5000 | X | = | - | 204000 |
| 204000 | = | 52101 5000 | X |
52101 5000 | X | = | 204000 |
| X | = | 204000 | ÷ | 52101 5000 |
| = | 204000 | × | 5000 52101 |
| = | 68000 | × | 5000 17367 |
| X | = | 340000000 17367 |
| X | = | 19577.35936 |