| ( | 2 | x | + | 18 | ) | ( | 2 | x | + | 18 | ) | = | ( | x | + | 20 | ) | ( | 3 | x | + | 16 | ) |
| 方程左边 = | 2 | x | ( | 2 | x | + | 18 | ) | + | 18 | ( | 2 | x | + | 18 | ) |
| = | 2 | x | × | 2 | x | + | 2 | x | × | 18 | + | 18 | ( | 2 | x | + | 18 | ) |
| = | 4 | x | x | + | 36 | x | + | 18 | ( | 2 | x | + | 18 | ) |
| = | 4 | x | x | + | 36 | x | + | 18 | × | 2 | x | + | 18 | × | 18 |
| = | 4 | x | x | + | 36 | x | + | 36 | x | + | 324 |
| = | 4 | x | x | + | 72 | x | + | 324 |
| 4 | x | x | + | 72 | x | + | 324 | = | ( | x | + | 20 | ) | ( | 3 | x | + | 16 | ) |
| 方程右边 = | x | ( | 3 | x | + | 16 | ) | + | 20 | ( | 3 | x | + | 16 | ) |
| = | x | × | 3 | x | + | x | × | 16 | + | 20 | ( | 3 | x | + | 16 | ) |
| = | x | × | 3 | x | + | 16 | x | + | 20 | × | 3 | x | + | 20 | × | 16 |
| = | x | × | 3 | x | + | 16 | x | + | 60 | x | + | 320 |
| = | x | × | 3 | x | + | 76 | x | + | 320 |
| 4 | x | x | + | 72 | x | + | 324 | = | x | × | 3 | x | + | 76 | x | + | 320 |