| ( | 3 | x | + | 12 | ) | ÷ | ( | 9 | x | + | 12 | ) | = | 9 | ÷ | 11 |
| 方程两边同时乘以: | ( | 9 | x | + | 12 | ) |
| ( | 3 | x | + | 12 | ) | = | 9 | ÷ | 11 | × | ( | 9 | x | + | 12 | ) |
| 3 | x | + | 12 | = | 9 | ÷ | 11 | × | ( | 9 | x | + | 12 | ) |
| 3 | x | + | 12 | = | 9 | ÷ | 11 | × | 9 | x | + | 9 | ÷ | 11 | × | 12 |
| 3 | x | + | 12 | = | 81 11 | x | + | 108 11 |
| 3 | x | − | 81 11 | x | = | 108 11 | − | 12 |
| - | 48 11 | x | = | 108 11 | − | 12 |
| - | 48 11 | x | = | - | 24 11 |
24 11 | = | 48 11 | x |
48 11 | x | = | 24 11 |
| x | = | 24 11 | ÷ | 48 11 |
| = | 24 11 | × | 11 48 |
| = | 1 | × | 1 2 |
| x | = | 1 2 |
| x | = | 0.5 |