| - | 31 | ÷ | ( | 2 | − | ( | - | 2 | x | + | 3 | ) | ) | + | 14 | = | 15 |
| 方程两边同时乘以: | ( | 2 | − | ( | - | 2 | x | + | 3 | ) | ) |
| - | 31 | + | 14 | ( | 2 | − | ( | - | 2 | x | + | 3 | ) | ) | = | 15 | ( | 2 | − | ( | - | 2 | x | + | 3 | ) | ) |
| - | 31 | + | 14 | × | 2 | − | 14 | ( | - | 2 | x | + | 3 | ) | = | 15 | ( | 2 | − | ( | - | 2 | x | + | 3 | ) | ) |
| - | 31 | + | 14 | × | 2 | − | 14 | ( | - | 2 | x | + | 3 | ) | = | 15 | × | 2 | − | 15 | ( | - | 2 | x | + | 3 | ) |
| - | 31 | + | 28 | − | 14 | ( | - | 2 | x | + | 3 | ) | = | 30 | − | 15 | ( | - | 2 | x | + | 3 | ) |
| - | 3 | − | 14 | ( | - | 2 | x | + | 3 | ) | = | 30 | − | 15 | ( | - | 2 | x | + | 3 | ) |
| - | 3 | + | 14 | × | 2 | x | − | 14 | × | 3 | = | 30 | − | 15 | ( | - | 2 | x | + | 3 | ) |
| - | 3 | + | 14 | × | 2 | x | − | 14 | × | 3 | = | 30 | + | 15 | × | 2 | x | − | 15 | × | 3 |
| - | 3 | + | 28 | x | − | 42 | = | 30 | + | 30 | x | − | 45 |
| - | 45 | + | 28 | x | = | - | 15 | + | 30 | x |
| 28 | x | − | 30 | x | = | - | 15 | + | 45 |
| - | 2 | x | = | - | 15 | + | 45 |
| - | 2 | x | = | 30 |
| - | 30 | = | 2 | x |
| 2 | x | = | - | 30 |
| x | = | - | 30 | ÷ | 2 |
| = | - | 30 | × | 1 2 |
| = | - | 15 | × | 1 |
| x | = | - | 15 |