| 5 | ( | 80 | − | t | ) | = | 19 | ( | t | − | 56 | ) |
| 方程左边 = | 5 | × | 80 | − | 5 | t |
| = | 400 | − | 5 | t |
| 400 | − | 5 | t | = | 19 | ( | t | − | 56 | ) |
| 方程右边 = | 19 | t | − | 19 | × | 56 |
| = | 19 | t | − | 1064 |
| 400 | − | 5 | t | = | 19 | t | − | 1064 |
| - | 5 | t | − | 19 | t | = | - | 1064 | − | 400 |
| - | 24 | t | = | - | 1064 | − | 400 |
| - | 24 | t | = | - | 1464 |
| 1464 | = | 24 | t |
| 24 | t | = | 1464 |
| t | = | 1464 | ÷ | 24 |
| = | 1464 | × | 1 24 |
| = | 61 | × | 1 |
| t | = | 61 |