30 100 | x | × | 90 100 | + | 90 100 | × | 20 100 | ( | 200 | − | x | ) | = | 200 | + | 277 10 |
| 方程左边 = | 27 100 | x | + | 9 50 | ( | 200 | − | x | ) |
27 100 | x | + | 9 50 | ( | 200 | − | x | ) | = | 200 | + | 277 10 |
| 方程左边 = | 27 100 | x | + | 9 50 | × | 200 | − | 9 50 | x |
| = | 27 100 | x | + | 36 | − | 9 50 | x |
| = | 9 100 | x | + | 36 |
9 100 | x | + | 36 | = | 200 | + | 277 10 |
| 方程右边 = | 2277 10 |
9 100 | x | + | 36 | = | 2277 10 |
9 100 | x | = | 2277 10 | − | 36 |
9 100 | x | = | 1917 10 |
| x | = | 1917 10 | ÷ | 9 100 |
| = | 1917 10 | × | 100 9 |
| = | 213 | × | 10 |
| x | = | 2130 |