| 168 | ÷ | ( | 1 | + | 2 | × | x% | ) | + | 240 | ÷ | ( | 1 | − | x% | ) | = | 408 |
| 方程两边同时乘以: | ( | 1 | + | 2 | × | x% | ) |
| 168 | + | 240 | ÷ | ( | 1 | − | x% | ) | × | ( | 1 | + | 2 | × | x% | ) | = | 408 | ( | 1 | + | 2 | × | x% | ) |
| 168 | + | 240 | ÷ | ( | 1 | − | x% | ) | × | 1 | + | 240 | ÷ | ( | 1 | − | x% | ) | × | 2 | × | x% | = | 408 | ( | 1 | + | 2 | × | x% | ) |
| 168 | + | 240 | ÷ | ( | 1 | − | x% | ) | × | 1 | + | 240 | ÷ | ( | 1 | − | x% | ) | × | 2 | × | x% | = | 408 | × | 1 | + | 408 | × | 2 | × | x% |
| 168 | + | 240 | ÷ | ( | 1 | − | x% | ) | + | 24 5 | ÷ | ( | 1 | − | x% | ) | × | x | = | 408 | + | 204 25 | x |
| 方程两边同时乘以: | ( | 1 | − | x% | ) |
| 168 | ( | 1 | − | x% | ) | + | 240 | + | 24 5 | x | = | 408 | ( | 1 | − | x% | ) | + | 204 25 | x | ( | 1 | − | x% | ) |
| 168 | × | 1 | − | 168 | × | x% | + | 240 | + | 24 5 | x | = | 408 | ( | 1 | − | x% | ) | + | 204 25 | x | ( | 1 | − | x% | ) |
| 168 | × | 1 | − | 168 | × | x% | + | 240 | + | 24 5 | x | = | 408 | × | 1 | − | 408 | × | x% | + | 204 25 | x | ( | 1 | − | x% | ) |
| 168 | − | 42 25 | x | + | 240 | + | 24 5 | x | = | 408 | − | 102 25 | x | + | 204 25 | x | ( | 1 | − | x% | ) |
| 408 | + | 78 25 | x | = | 408 | − | 102 25 | x | + | 204 25 | x | ( | 1 | − | x% | ) |
| 408 | + | 78 25 | x | = | 408 | − | 102 25 | x | + | 204 25 | x | × | 1 | − | 204 25 | x | × | x% |
| 408 | + | 78 25 | x | = | 408 | − | 102 25 | x | + | 204 25 | x | − | 51 625 | x | x |
| 408 | + | 78 25 | x | = | 408 | + | 102 25 | x | − | 51 625 | x | x |