| 0 | = | 2000 | × | 50000 | − | ( | ( | 1000 | + | 150 | ) | × | 50000 | + | c | ) |
| 方程右边 = | 100000000 | − | ( | ( | 1000 | + | 150 | ) | × | 50000 | + | c | ) |
| 0 | = | 100000000 | − | ( | ( | 1000 | + | 150 | ) | × | 50000 | + | c | ) |
| 方程右边 = | 100000000 | − | ( | 1000 | + | 150 | ) | × | 50000 | − | c |
| = | 100000000 | − | 1000 | × | 50000 | − | 150 | × | 50000 | − | c |
| = | 100000000 | − | 50000000 | − | 7500000 | − | c |
| = | 42500000 | − | c |
| 0 | = | 42500000 | − | c |
| c | = | 42500000 | − | 0 |
| c | = | 42500000 |