| 2000 | + | 2000 | ( | 1 | + | x | ) | + | 2000 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 8720 |
| 方程左边 = | 2000 | + | 2000 | × | 1 | + | 2000 | x | + | 2000 | ( | 1 | + | x | ) | ( | 1 | + | x | ) |
| = | 2000 | + | 2000 | + | 2000 | x | + | 2000 | ( | 1 | + | x | ) | ( | 1 | + | x | ) |
| = | 4000 | + | 2000 | x | + | 2000 | ( | 1 | + | x | ) | ( | 1 | + | x | ) |
| = | 4000 | + | 2000 | x | + | 2000 | × | 1 | ( | 1 | + | x | ) | + | 2000 | x | ( | 1 | + | x | ) |
| = | 4000 | + | 2000 | x | + | 2000 | ( | 1 | + | x | ) | + | 2000 | x | ( | 1 | + | x | ) |
| = | 4000 | + | 2000 | x | + | 2000 | × | 1 | + | 2000 | x | + | 2000 | x | ( | 1 | + | x | ) |
| = | 4000 | + | 2000 | x | + | 2000 | + | 2000 | x | + | 2000 | x | ( | 1 | + | x | ) |
| = | 6000 | + | 4000 | x | + | 2000 | x | ( | 1 | + | x | ) |
| = | 6000 | + | 4000 | x | + | 2000 | x | × | 1 | + | 2000 | x | x |
| = | 6000 | + | 4000 | x | + | 2000 | x | + | 2000 | x | x |
| = | 6000 | + | 6000 | x | + | 2000 | x | x |
| 6000 | + | 6000 | x | + | 2000 | x | x | = | 8720 |
| x1= | - | 17 5 |
| x2= | 2 5 |