| ( | 100 | + | x | ) | x | ÷ | ( | ( | 1775 | − | x | ) | × | 100 | ) | = | 12 5 |
| 方程两边同时乘以: | ( | ( | 1775 | − | x | ) | × | 100 | ) |
| ( | 100 | + | x | ) | x | = | 12 5 | ( | ( | 1775 | − | x | ) | × | 100 | ) |
| 100 | x | + | x | x | = | 12 5 | ( | ( | 1775 | − | x | ) | × | 100 | ) |
| 100 | x | + | x | x | = | 12 5 | ( | 1775 | − | x | ) | × | 100 |
| 100 | x | + | x | x | = | 240 | ( | 1775 | − | x | ) |
| 100 | x | + | x | x | = | 240 | × | 1775 | − | 240 | x |
| 100 | x | + | x | x | = | 426000 | − | 240 | x |