| ( | x | − | 300 | ) | × | 3 4 | ÷ | 1000 | = | ( | x | − | 300 | − | 440 | ) | × | 3 4 | ÷ | 800 |
| 方程左边 = | ( | x | − | 300 | ) | × | 3 4000 |
| ( | x | − | 300 | ) | × | 3 4000 | = | ( | x | − | 300 | − | 440 | ) | × | 3 4 | ÷ | 800 |
| 方程左边 = | x | × | 3 4000 | − | 300 | × | 3 4000 |
| = | x | × | 3 4000 | − | 9 40 |
3 4000 | x | − | 9 40 | = | ( | x | − | 300 | − | 440 | ) | × | 3 4 | ÷ | 800 |
| 方程右边 = | ( | x | − | 300 | − | 440 | ) | × | 3 3200 |
3 4000 | x | − | 9 40 | = | ( | x | − | 300 | − | 440 | ) | × | 3 3200 |
| 方程右边 = | x | × | 3 3200 | − | 300 | × | 3 3200 | − | 440 | × | 3 3200 |
| = | x | × | 3 3200 | − | 9 32 | − | 33 80 |
| = | 3 3200 | x | − | 111 160 |
3 4000 | x | − | 9 40 | = | 3 3200 | x | − | 111 160 |
3 4000 | x | − | 3 3200 | x | = | - | 111 160 | + | 9 40 |
| - | 3 16000 | x | = | - | 111 160 | + | 9 40 |
| - | 3 16000 | x | = | - | 15 32 |
15 32 | = | 3 16000 | x |
3 16000 | x | = | 15 32 |
| x | = | 15 32 | ÷ | 3 16000 |
| = | 15 32 | × | 16000 3 |
| = | 5 | × | 500 |
| x | = | 2500 |