| x | ÷ | ( | 12 | − | 400 | ÷ | 3 | ) | + | x | ( | 12 | + | 400 | ÷ | 3 | ) | = | 36 5 |
| 方程两边同时乘以: | ( | 12 | − | 400 | ÷ | 3 | ) |
| x | + | x | ( | 12 | + | 400 | ÷ | 3 | ) | ( | 12 | − | 400 | ÷ | 3 | ) | = | 36 5 | ( | 12 | − | 400 | ÷ | 3 | ) |
| x | + | x | × | 12 | ( | 12 | − | 400 | ÷ | 3 | ) | + | x | × | 400 | ÷ | 3 | × | ( | 12 | − | 400 | ÷ | 3 | ) | = | 36 5 | ( | 12 | − | 400 | ÷ | 3 | ) |
| x | + | x | × | 12 | ( | 12 | − | 400 | ÷ | 3 | ) | + | x | × | 400 | ÷ | 3 | × | ( | 12 | − | 400 | ÷ | 3 | ) | = | 36 5 | × | 12 | − | 36 5 | × | 400 | ÷ | 3 |
| x | + | x | × | 12 | ( | 12 | − | 400 | ÷ | 3 | ) | + | x | × | 400 3 | ( | 12 | − | 400 | ÷ | 3 | ) | = | 432 5 | − | 960 |
| x | + | x | × | 12 | ( | 12 | − | 400 | ÷ | 3 | ) | + | x | × | 400 3 | ( | 12 | − | 400 | ÷ | 3 | ) | = | - | 4368 5 |
| x | + | x | × | 12 | × | 12 | − | x | × | 12 | × | 400 | ÷ | 3 | + | x | × | 400 3 | ( | 12 | − | 400 | ÷ | 3 | ) | = | - | 4368 5 |
| x | + | x | × | 144 | − | x | × | 1600 | + | x | × | 400 3 | ( | 12 | − | 400 | ÷ | 3 | ) | = | - | 4368 5 |
| - | 1455 | x | + | x | × | 400 3 | ( | 12 | − | 400 | ÷ | 3 | ) | = | - | 4368 5 |
| - | 1455 | x | + | x | × | 400 3 | × | 12 | − | x | × | 400 3 | × | 400 | ÷ | 3 | = | - | 4368 5 |
| - | 1455 | x | + | x | × | 1600 | − | x | × | 160000 9 | = | - | 4368 5 |
| - | 158695 9 | x | = | - | 4368 5 |
4368 5 | = | 158695 9 | x |
158695 9 | x | = | 4368 5 |
| x | = | 4368 5 | ÷ | 158695 9 |
| = | 4368 5 | × | 9 158695 |
| x | = | 39312 793475 |
| x | = | 0.049544 |