| ( | 2 | + | 2 | x | ) | ( | 8 5 | + | 2 | x | ) | = | 37 4 |
| 方程左边 = | 2 | ( | 8 5 | + | 2 | x | ) | + | 2 | x | ( | 8 5 | + | 2 | x | ) |
| = | 2 | × | 8 5 | + | 2 | × | 2 | x | + | 2 | x | ( | 8 5 | + | 2 | x | ) |
| = | 16 5 | + | 4 | x | + | 2 | x | ( | 8 5 | + | 2 | x | ) |
| = | 16 5 | + | 4 | x | + | 2 | x | × | 8 5 | + | 2 | x | × | 2 | x |
| = | 16 5 | + | 4 | x | + | 16 5 | x | + | 4 | x | x |
| = | 16 5 | + | 36 5 | x | + | 4 | x | x |
16 5 | + | 36 5 | x | + | 4 | x | x | = | 37 4 |