| 4 | b | b | b | ÷ | ( | ( | 1 | − | b | ) | ( | 1 | − | b | ) | ) | = | 128 5 |
| 方程两边同时乘以: | ( | ( | 1 | − | b | ) | ( | 1 | − | b | ) | ) |
| 4 | b | b | b | = | 128 5 | ( | ( | 1 | − | b | ) | ( | 1 | − | b | ) | ) |
| 4 | b | b | b | = | 128 5 | ( | 1 | − | b | ) | ( | 1 | − | b | ) |
| 4 | b | b | b | = | 128 5 | × | 1 | ( | 1 | − | b | ) | − | 128 5 | b | ( | 1 | − | b | ) |
| 4 | b | b | b | = | 128 5 | ( | 1 | − | b | ) | − | 128 5 | b | ( | 1 | − | b | ) |
| 4 | b | b | b | = | 128 5 | × | 1 | − | 128 5 | b | − | 128 5 | b | ( | 1 | − | b | ) |
| 4 | b | b | b | = | 128 5 | − | 128 5 | b | − | 128 5 | b | ( | 1 | − | b | ) |
| 4 | b | b | b | = | 128 5 | − | 128 5 | b | − | 128 5 | b | × | 1 | + | 128 5 | b | b |
| 4 | b | b | b | = | 128 5 | − | 128 5 | b | − | 128 5 | b | + | 128 5 | b | b |
| 4 | b | b | b | = | 128 5 | − | 256 5 | b | + | 128 5 | b | b |