| 1 | ÷ | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) | × | I | − | 3 | = | ( | 1 50 | − | I | ) | × | 8400 | ÷ | 43 |
| 方程两边同时乘以: | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) | = | ( | 1 50 | − | I | ) | × | 8400 | ÷ | 43 | × | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 | × | 1 | ÷ | 390 | − | 3 | × | 1 | ÷ | 510 | = | ( | 1 50 | − | I | ) | × | 8400 | ÷ | 43 | × | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 | × | 1 | ÷ | 390 | − | 3 | × | 1 | ÷ | 510 | = | 1 50 | × | 8400 | ÷ | 43 | × | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) | − | I | × | 8400 | ÷ | 43 | × | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 1 130 | − | 1 170 | = | 168 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) | − | I | × | 8400 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 221 | = | 168 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) | − | I | × | 8400 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 221 | = | 168 43 | × | 1 | ÷ | 390 | + | 168 43 | × | 1 | ÷ | 510 | − | I | × | 8400 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 221 | = | 28 2795 | + | 28 3655 | − | I | × | 8400 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 221 | = | 168 9503 | − | I | × | 8400 43 | ( | 1 | ÷ | 390 | + | 1 | ÷ | 510 | ) |
| 1 | I | − | 3 221 | = | 168 9503 | − | I | × | 8400 43 | × | 1 | ÷ | 390 | − | I | × | 8400 43 | × | 1 | ÷ | 510 |
| 1 | I | − | 3 221 | = | 168 9503 | − | I | × | 280 559 | − | I | × | 280 731 |
| 1 | I | − | 3 221 | = | 168 9503 | − | 8400 9503 | I |
| 1 | I | + | 8400 9503 | I | = | 168 9503 | + | 3 221 |
17903 9503 | I | = | 168 9503 | + | 3 221 |
17903 9503 | I | = | 297 9503 |
| I | = | 297 9503 | ÷ | 17903 9503 |
| = | 297 9503 | × | 9503 17903 |
| = | 297 | × | 1 17903 |
| I | = | 297 17903 |
| I | = | 0.016589 |