| 2400 | ( | x | + | 5 | ) | × | 2 | ÷ | 3 | × | x | ( | x | + | 5 | ) | = | 3700 | x |
| 方程左边 = | 1600 | ( | x | + | 5 | ) | x | ( | x | + | 5 | ) |
| 1600 | ( | x | + | 5 | ) | x | ( | x | + | 5 | ) | = | 3700 | x |
| 方程左边 = | 1600 | x | x | ( | x | + | 5 | ) | + | 1600 | × | 5 | x | ( | x | + | 5 | ) |
| = | 1600 | x | x | ( | x | + | 5 | ) | + | 8000 | x | ( | x | + | 5 | ) |
| = | 1600 | x | x | x | + | 1600 | x | x | × | 5 | + | 8000 | x | ( | x | + | 5 | ) |
| = | 1600 | x | x | x | + | 8000 | x | x | + | 8000 | x | ( | x | + | 5 | ) |
| = | 1600 | x | x | x | + | 8000 | x | x | + | 8000 | x | x | + | 8000 | x |
| = | 1600 | x | x | x | + | 8000 | x | x | + | 8000 | x | x | + | 40000 | x |
| 1600 | x | x | x | + | 8000 | x | x | + | 8000 | x | x | + | 40000 | x | = | 3700 | x |
| x1=0 |