| 12 | ( | t | − | 56 | ) | = | 16 | ( | 80 | − | t | ) |
| 方程左边 = | 12 | t | − | 12 | × | 56 |
| = | 12 | t | − | 672 |
| 12 | t | − | 672 | = | 16 | ( | 80 | − | t | ) |
| 方程右边 = | 16 | × | 80 | − | 16 | t |
| = | 1280 | − | 16 | t |
| 12 | t | − | 672 | = | 1280 | − | 16 | t |
| 12 | t | + | 16 | t | = | 1280 | + | 672 |
| 28 | t | = | 1280 | + | 672 |
| 28 | t | = | 1952 |
| t | = | 1952 | ÷ | 28 |
| = | 1952 | × | 1 28 |
| = | 488 | × | 1 7 |
| t | = | 488 7 |
| t | = | 69.714286 |