| x | + | ( | 150 | − | x | ) | × | 21 100 | ÷ | 150 | = | 3 5 |
| 方程左边 = | x | + | ( | 150 | − | x | ) | × | 7 5000 |
| x | + | ( | 150 | − | x | ) | × | 7 5000 | = | 3 5 |
| 方程左边 = | x | + | 150 | × | 7 5000 | − | x | × | 7 5000 |
| = | x | + | 21 100 | − | x | × | 7 5000 |
| = | 4993 5000 | x | + | 21 100 |
4993 5000 | x | + | 21 100 | = | 3 5 |
4993 5000 | x | = | 3 5 | − | 21 100 |
4993 5000 | x | = | 39 100 |
| x | = | 39 100 | ÷ | 4993 5000 |
| = | 39 100 | × | 5000 4993 |
| = | 39 | × | 50 4993 |
| x | = | 1950 4993 |
| x | = | 0.390547 |