| - | 3 | ÷ | ( | 7 | − | ( | 3 | x | − | 12 | ) | ) | + | 19 | = | 16 |
| 方程两边同时乘以: | ( | 7 | − | ( | 3 | x | − | 12 | ) | ) |
| - | 3 | + | 19 | ( | 7 | − | ( | 3 | x | − | 12 | ) | ) | = | 16 | ( | 7 | − | ( | 3 | x | − | 12 | ) | ) |
| - | 3 | + | 19 | × | 7 | − | 19 | ( | 3 | x | − | 12 | ) | = | 16 | ( | 7 | − | ( | 3 | x | − | 12 | ) | ) |
| - | 3 | + | 19 | × | 7 | − | 19 | ( | 3 | x | − | 12 | ) | = | 16 | × | 7 | − | 16 | ( | 3 | x | − | 12 | ) |
| - | 3 | + | 133 | − | 19 | ( | 3 | x | − | 12 | ) | = | 112 | − | 16 | ( | 3 | x | − | 12 | ) |
| 130 | − | 19 | ( | 3 | x | − | 12 | ) | = | 112 | − | 16 | ( | 3 | x | − | 12 | ) |
| 130 | − | 19 | × | 3 | x | + | 19 | × | 12 | = | 112 | − | 16 | ( | 3 | x | − | 12 | ) |
| 130 | − | 19 | × | 3 | x | + | 19 | × | 12 | = | 112 | − | 16 | × | 3 | x | + | 16 | × | 12 |
| 130 | − | 57 | x | + | 228 | = | 112 | − | 48 | x | + | 192 |
| 358 | − | 57 | x | = | 304 | − | 48 | x |
| - | 57 | x | + | 48 | x | = | 304 | − | 358 |
| - | 9 | x | = | 304 | − | 358 |
| - | 9 | x | = | - | 54 |
| 54 | = | 9 | x |
| 9 | x | = | 54 |
| x | = | 54 | ÷ | 9 |
| = | 54 | × | 1 9 |
| = | 6 | × | 1 |
| x | = | 6 |