| ( | x | × | 1 20 | ) | ÷ | ( | x | × | 9 10 | ) | = | 142 5 |
| 方程两边同时乘以: | ( | x | × | 9 10 | ) |
| ( | x | × | 1 20 | ) | = | 142 5 | ( | x | × | 9 10 | ) |
| x | × | 1 20 | = | 142 5 | ( | x | × | 9 10 | ) |
| x | × | 1 20 | = | 142 5 | x | × | 9 10 |
| x | × | 1 20 | = | 639 25 | x |
1 20 | x | − | 639 25 | x | = | 0 |
| - | 2551 100 | x | = | 0 |
| - | 0 | = | 2551 100 | x |
2551 100 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 2551 100 |
| = | - | 0 | × | 100 2551 |
| x | = | 0 |
| x | = | 0 |