| ( | 8 | + | x | ) | ( | 3 | + | x | ) | ÷ | 2 | = | x | x |
| 方程左边 = | 8 | ( | 3 | + | x | ) | × | 1 2 | + | x | ( | 3 | + | x | ) | × | 1 2 |
| = | 4 | ( | 3 | + | x | ) | + | x | ( | 3 | + | x | ) | × | 1 2 |
| = | 4 | × | 3 | + | 4 | x | + | x | ( | 3 | + | x | ) | × | 1 2 |
| = | 12 | + | 4 | x | + | x | ( | 3 | + | x | ) | × | 1 2 |
| = | 12 | + | 4 | x | + | x | × | 3 | × | 1 2 | + | x | x | × | 1 2 |
| = | 12 | + | 4 | x | + | x | × | 3 2 | + | x | x | × | 1 2 |
| = | 12 | + | 11 2 | x | + | x | x | × | 1 2 |
| 12 | + | 11 2 | x | + | x | x | × | 1 2 | = | x | x |