| ( | 63 | − | 63 | ) | ÷ | ( | 63 | − | 48 | ) | = | ( | 85 | − | t | ) | ÷ | ( | t | − | 71 | ) |
| 方程两边同时乘以: | ( | 63 | − | 48 | ) | , | ( | t | − | 71 | ) |
| ( | 63 | − | 63 | ) | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 63 | − | 48 | ) |
| 63 | ( | t | − | 71 | ) | − | 63 | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 63 | − | 48 | ) |
| 63 | ( | t | − | 71 | ) | − | 63 | ( | t | − | 71 | ) | = | 85 | ( | 63 | − | 48 | ) | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 63 | × | 71 | − | 63 | ( | t | − | 71 | ) | = | 85 | ( | 63 | − | 48 | ) | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 63 | × | 71 | − | 63 | ( | t | − | 71 | ) | = | 85 | × | 63 | − | 85 | × | 48 | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 4473 | − | 63 | ( | t | − | 71 | ) | = | 5355 | − | 4080 | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 4473 | − | 63 | ( | t | − | 71 | ) | = | 1275 | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 4473 | − | 63 | t | + | 63 | × | 71 | = | 1275 | − | t | ( | 63 | − | 48 | ) |
| 63 | t | − | 4473 | − | 63 | t | + | 63 | × | 71 | = | 1275 | − | t | × | 63 | + | t | × | 48 |
| 63 | t | − | 4473 | − | 63 | t | + | 4473 | = | 1275 | − | t | × | 63 | + | t | × | 48 |
| 0 | t | − | 0 | = | 1275 | − | 15 | t |
| 15 | t | = | 1275 | + | 0 |
| 15 | t | = | 1275 |
| t | = | 1275 | ÷ | 15 |
| = | 1275 | × | 1 15 |
| = | 85 | × | 1 |
| t | = | 85 |