| ( | x | − | 0 | ) | ( | 1 | − | 30 100 | ) | ÷ | 200000 | = | ( | x | − | 500000 | ) | ( | 1 | − | 30 100 | ) | ÷ | 100000 |
| 方程左边 = | x | ( | 1 | − | 30 100 | ) | × | 1 200000 | − | 0 | ( | 1 | − | 30 100 | ) | × | 1 200000 |
| = | x | ( | 1 | − | 30 100 | ) | × | 1 200000 | − | 0 | ( | 1 | − | 30 100 | ) |
| = | x | × | 1 | × | 1 200000 | − | x | × | 30 100 | × | 1 200000 | − | 0 | ( | 1 | − | 30 100 | ) |
| = | x | × | 1 200000 | − | x | × | 3 2000000 | − | 0 | ( | 1 | − | 30 100 | ) |