| 150000 | ÷ | ( | 30 | − | Y | ) | = | 3000000 | + | Y | × | 10000 | ÷ | ( | 180 | − | 6 | Y | ) |
| 方程两边同时乘以: | ( | 30 | − | Y | ) | , | ( | 180 | − | 6 | Y | ) |
| 150000 | ( | 180 | − | 6 | Y | ) | = | 3000000 | ( | 30 | − | Y | ) | ( | 180 | − | 6 | Y | ) | + | Y | × | 10000 | ( | 30 | − | Y | ) |
| 150000 | × | 180 | − | 150000 | × | 6 | Y | = | 3000000 | ( | 30 | − | Y | ) | ( | 180 | − | 6 | Y | ) | + | Y | × | 10000 | ( | 30 | − | Y | ) |
| 150000 | × | 180 | − | 150000 | × | 6 | Y | = | 3000000 | × | 30 | ( | 180 | − | 6 | Y | ) | − | 3000000 | Y | ( | 180 | − | 6 | Y | ) | + | Y | × | 10000 | ( | 30 | − | Y | ) |
| 27000000 | − | 900000 | Y | = | 90000000 | ( | 180 | − | 6 | Y | ) | − | 3000000 | Y | ( | 180 | − | 6 | Y | ) | + | Y | × | 10000 | ( | 30 | − | Y | ) |
| 27000000 | − | 900000 | Y | = | 90000000 | × | 180 | − | 90000000 | × | 6 | Y | − | 3000000 | Y | ( | 180 | − | 6 | Y | ) | + | Y | × | 10000 | ( | 30 | − | Y | ) |