| 5 | × | 1 | ÷ | ( | 1 | + | r | ) | + | 5 | × | 1 | ÷ | ( | 1 | + | r | ) | × | 1 | ÷ | ( | 1 | + | r | ) | + | 5 | × | 1 | ÷ | ( | 1 | + | r | ) | × | 1 | = | 5139 50 |
| 方程两边同时乘以: | ( | 1 | + | r | ) |
| 5 | × | 1 | + | 5 | × | 1 | × | 1 | ÷ | ( | 1 | + | r | ) | + | 5 | × | 1 | × | 1 | ÷ | ( | 1 | + | r | ) | × | 1 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | ( | 1 | + | r | ) |
| 5 | × | 1 | + | 5 | × | 1 | × | 1 | ÷ | ( | 1 | + | r | ) | + | 5 | × | 1 | × | 1 | ÷ | ( | 1 | + | r | ) | × | 1 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | × | 1 | + | 5139 50 | r |
| 5 | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r |
| 方程两边同时乘以: | ( | 1 | + | r | ) |
| 5 | ( | 1 | + | r | ) | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) |
| 5 | × | 1 | + | 5 | r | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) |
| 5 | × | 1 | + | 5 | r | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | × | 1 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) |
| 5 | + | 5 | r | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) |
| 10 | + | 5 | r | + | 5 | ÷ | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | ÷ | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) |
| 方程两边同时乘以: | ( | 1 | + | r | ) |
| 10 | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 10 | × | 1 | + | 10 | r | + | 5 | r | ( | 1 | + | r | ) | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 10 | × | 1 | + | 10 | r | + | 5 | r | ( | 1 | + | r | ) | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | × | 1 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 10 | + | 10 | r | + | 5 | r | ( | 1 | + | r | ) | + | 5 | + | 5 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 15 | + | 10 | r | + | 5 | r | ( | 1 | + | r | ) | + | 5 | ÷ | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 方程两边同时乘以: | ( | 1 | + | r | ) |
| 15 | ( | 1 | + | r | ) | + | 10 | r | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5 | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) |
| 15 | × | 1 | + | 15 | r | + | 10 | r | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5 | = | 5139 50 | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) |
| 15 | × | 1 | + | 15 | r | + | 10 | r | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5 | = | 5139 50 | × | 1 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 |
| 15 | + | 15 | r | + | 10 | r | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5 | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r |
| 20 | + | 15 | r | + | 10 | r | ( | 1 | + | r | ) | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r |
| 20 | + | 15 | r | + | 10 | r | × | 1 | + | 10 | r | r | + | 5 | r | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | ( | 1 | + | r | ) | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r |
| 20 | + | 15 | r | + | 10 | r | × | 1 | + | 10 | r | r | + | 5 | r | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | × | 1 | + | 5139 50 | r | r | + | 5139 50 | r | ( | 1 | + | r | ) |
| 20 | + | 15 | r | + | 10 | r | + | 10 | r | r | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 50 | r | + | 5139 50 | r | + | 5139 50 | r | r | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) |
| 20 | + | 25 | r | + | 10 | r | r | + | 5 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | = | 5139 50 | + | 5139 25 | r | + | 5139 50 | r | r | + | 5139 50 | r | ( | 1 | + | r | ) | ( | 1 | + | r | ) | + | 5139 50 | r |