| ( | 6 | a | + | 7 | ) | ( | 3 | a | + | 4 | ) | ( | a | + | 1 | ) | = | 1 |
| 方程左边 = | 6 | a | ( | 3 | a | + | 4 | ) | ( | a | + | 1 | ) | + | 7 | ( | 3 | a | + | 4 | ) | ( | a | + | 1 | ) |
| = | 6 | a | × | 3 | a | ( | a | + | 1 | ) | + | 6 | a | × | 4 | ( | a | + | 1 | ) | + | 7 | ( | 3 | a | + | 4 | ) | ( | a | + | 1 | ) |
| = | 18 | a | a | ( | a | + | 1 | ) | + | 24 | a | ( | a | + | 1 | ) | + | 7 | ( | 3 | a | + | 4 | ) | ( | a | + | 1 | ) |
| = | 18 | a | a | a | + | 18 | a | a | × | 1 | + | 24 | a | ( | a | + | 1 | ) | + | 7 |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | ( | a | + | 1 | ) | + | 7 | ( | 3 | a | + | 4 | ) |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 24 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 45 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 45 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 45 | a |
| = | 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 73 | a |
| 18 | a | a | a | + | 18 | a | a | + | 24 | a | a | + | 73 | a | = | 1 |