| ( | 40 | x | + | 22 | ) | ( | 1 | + | 2 | x | ) | × | 40 | = | 4000 |
| 方程左边 = | 40 | x | ( | 1 | + | 2 | x | ) | × | 40 | + | 22 | ( | 1 | + | 2 | x | ) | × | 40 |
| = | 1600 | x | ( | 1 | + | 2 | x | ) | + | 880 | ( | 1 | + | 2 | x | ) |
| = | 1600 | x | × | 1 | + | 1600 | x | × | 2 | x | + | 880 | ( | 1 | + | 2 | x | ) |
| = | 1600 | x | + | 3200 | x | x | + | 880 | ( | 1 | + | 2 | x | ) |
| = | 1600 | x | + | 3200 | x | x | + | 880 | × | 1 | + | 880 | × | 2 | x |
| = | 1600 | x | + | 3200 | x | x | + | 880 | + | 1760 | x |
| = | 3360 | x | + | 3200 | x | x | + | 880 |
| 3360 | x | + | 3200 | x | x | + | 880 | = | 4000 |