| ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ÷ | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | = | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | ÷ | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) |
| 方程两边同时乘以: | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | , | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) |
| ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| ( | 16 | − | 9 | x | ) | ÷ | 5 | × | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| ( | 16 | − | 9 | x | ) | ÷ | 5 | × | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | ( | 12 | − | 3 | x | ) | ÷ | 5 | × | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | × | 1 5 | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | − | 9 | x | × | 1 5 | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | ( | 12 | − | 3 | x | ) | × | 1 5 | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | × | 1 5 | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | − | 9 | x | × | 1 5 | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 | × | 1 5 | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | − | 3 | x | × | 1 5 | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
16 5 | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 5 | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
16 5 | × | 5 | − | 16 5 | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 5 | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
16 5 | × | 5 | − | 16 5 | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 5 | ( | 12 | − | 3 | x | ) | ÷ | 5 | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 5 | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 25 | ( | 12 | − | 3 | x | ) | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 5 | ( | 16 | − | 9 | x | ) | ÷ | 5 | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 25 | ( | 12 | − | 3 | x | ) | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 5 | ( | 16 | − | 9 | x | ) | ÷ | 5 | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 12 25 | × | 12 | − | 12 25 | × | 3 | x | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 25 | ( | 16 | − | 9 | x | ) | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 144 25 | − | 36 25 | x | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 25 | × | 16 | + | 16 25 | × | 9 | x | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 144 25 | − | 36 25 | x | − | 3 5 | x | ( | ( | 12 | − | 3 | x | ) | ÷ | 5 | ) |
| 16 | − | 16 25 | × | 16 | + | 16 25 | × | 9 | x | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 144 25 | − | 36 25 | x | − | 3 5 | x | ( | 12 | − | 3 | x | ) | ÷ | 5 |
| 16 | − | 256 25 | + | 144 25 | x | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 144 25 | − | 36 25 | x | − | 3 25 | x | ( | 12 | − | 3 | x | ) |
144 25 | + | 144 25 | x | − | 9 5 | x | ( | 5 | − | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | ) | = | 144 25 | − | 36 25 | x | − | 3 25 | x | ( | 12 | − | 3 | x | ) |
144 25 | + | 144 25 | x | − | 9 5 | x | × | 5 | + | 9 5 | x | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | = | 144 25 | − | 36 25 | x | − | 3 25 | x | ( | 12 | − | 3 | x | ) |
144 25 | + | 144 25 | x | − | 9 5 | x | × | 5 | + | 9 5 | x | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | = | 144 25 | − | 36 25 | x | − | 3 25 | x | × | 12 | + | 3 25 | x | × | 3 | x |
144 25 | + | 144 25 | x | − | 9 | x | + | 9 5 | x | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | = | 144 25 | − | 36 25 | x | − | 36 25 | x | + | 9 25 | x | x |
144 25 | − | 81 25 | x | + | 9 5 | x | ( | ( | 16 | − | 9 | x | ) | ÷ | 5 | ) | = | 144 25 | − | 72 25 | x | + | 9 25 | x | x |
144 25 | − | 81 25 | x | + | 9 5 | x | ( | 16 | − | 9 | x | ) | ÷ | 5 | = | 144 25 | − | 72 25 | x | + | 9 25 | x | x |
144 25 | − | 81 25 | x | + | 9 25 | x | ( | 16 | − | 9 | x | ) | = | 144 25 | − | 72 25 | x | + | 9 25 | x | x |
144 25 | − | 81 25 | x | + | 9 25 | x | × | 16 | − | 9 25 | x | × | 9 | x | = | 144 25 | − | 72 25 | x | + | 9 25 | x | x |
144 25 | − | 81 25 | x | + | 144 25 | x | − | 81 25 | x | x | = | 144 25 | − | 72 25 | x | + | 9 25 | x | x |
| x2= | 3 2 |