| ( | y | × | 1 20 | ) | ÷ | ( | y | × | 9 100 | ) | = | 142 5 |
| 方程两边同时乘以: | ( | y | × | 9 100 | ) |
| ( | y | × | 1 20 | ) | = | 142 5 | ( | y | × | 9 100 | ) |
| y | × | 1 20 | = | 142 5 | ( | y | × | 9 100 | ) |
| y | × | 1 20 | = | 142 5 | y | × | 9 100 |
| y | × | 1 20 | = | 639 250 | y |
1 20 | y | − | 639 250 | y | = | 0 |
| - | 1253 500 | y | = | 0 |
| - | 0 | = | 1253 500 | y |
1253 500 | y | = | - | 0 |
| y | = | - | 0 | ÷ | 1253 500 |
| = | - | 0 | × | 500 1253 |
| y | = | 0 |
| y | = | 0 |