| 12 | × | 6 | − | ( | 6 | + | 2 | t | ) | ÷ | 2 | − | t | ( | 6 | − | 2 | t | ) | ÷ | 2 | = | 22 |
| 方程左边 = | 72 | − | ( | 6 | + | 2 | t | ) | × | 1 2 | − | t | ( | 6 | − | 2 | t | ) | × | 1 2 |
| 72 | − | ( | 6 | + | 2 | t | ) | × | 1 2 | − | t | ( | 6 | − | 2 | t | ) | × | 1 2 | = | 22 |
| 方程左边 = | 72 | − | 6 | × | 1 2 | − | 2 | t | × | 1 2 | − | t | ( | 6 | − | 2 | t | ) | × | 1 2 |
| = | 72 | − | 3 | − | 1 | t | − | t | ( | 6 | − | 2 | t | ) | × | 1 2 |
| = | 69 | − | 1 | t | − | t | ( | 6 | − | 2 | t | ) | × | 1 2 |
| = | 69 | − | 1 | t | − | t | × | 6 | × | 1 2 | + | t | × | 2 | t | × | 1 2 |
| = | 69 | − | 1 | t | − | t | × | 3 | + | t | × | 1 | t |
| = | 69 | − | 4 | t | + | t | × | 1 | t |
| 69 | − | 4 | t | + | t | × | 1 | t | = | 22 |