| 200 | ( | 1 | + | x | ) | × | 150 | ( | 1 | − | 10 | ÷ | 9 | × | x | ) | = | 20000 |
| 方程左边 = | 30000 | ( | 1 | + | x | ) | ( | 1 | − | 10 | ÷ | 9 | × | x | ) |
| 30000 | ( | 1 | + | x | ) | ( | 1 | − | 10 | ÷ | 9 | × | x | ) | = | 20000 |
| 方程左边 = | 30000 | × | 1 | ( | 1 | − | 10 | ÷ | 9 | × | x | ) | + | 30000 | x | ( | 1 | − | 10 | ÷ | 9 | × | x | ) |
| = | 30000 | ( | 1 | − | 10 | ÷ | 9 | × | x | ) | + | 30000 | x | ( | 1 | − | 10 | ÷ | 9 | × | x | ) |
| = | 30000 | × | 1 | − | 30000 | × | 10 | ÷ | 9 | × | x | + | 30000 | x | ( | 1 | − | 10 | ÷ | 9 | × | x | ) |
| = | 30000 | − | 100000 3 | x | + | 30000 | x | ( | 1 | − | 10 | ÷ | 9 | × | x | ) |
| = | 30000 | − | 100000 3 | x | + | 30000 | x | × | 1 | − | 30000 | x | × | 10 | ÷ | 9 | × | x |
| = | 30000 | − | 100000 3 | x | + | 30000 | x | − | 100000 3 | x | x |
| = | 30000 | − | 10000 3 | x | − | 100000 3 | x | x |
| 30000 | − | 10000 3 | x | − | 100000 3 | x | x | = | 20000 |
| x1= | - | 3 5 |
| x2= | 1 2 |