| ( | 63 | − | 50 | ) | ÷ | ( | 50 | − | 48 | ) | = | ( | 85 | − | t | ) | ÷ | ( | t | − | 71 | ) |
| 方程两边同时乘以: | ( | 50 | − | 48 | ) | , | ( | t | − | 71 | ) |
| ( | 63 | − | 50 | ) | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 50 | − | 48 | ) |
| 63 | ( | t | − | 71 | ) | − | 50 | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 50 | − | 48 | ) |
| 63 | ( | t | − | 71 | ) | − | 50 | ( | t | − | 71 | ) | = | 85 | ( | 50 | − | 48 | ) | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 63 | × | 71 | − | 50 | ( | t | − | 71 | ) | = | 85 | ( | 50 | − | 48 | ) | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 63 | × | 71 | − | 50 | ( | t | − | 71 | ) | = | 85 | × | 50 | − | 85 | × | 48 | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 4473 | − | 50 | ( | t | − | 71 | ) | = | 4250 | − | 4080 | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 4473 | − | 50 | ( | t | − | 71 | ) | = | 170 | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 4473 | − | 50 | t | + | 50 | × | 71 | = | 170 | − | t | ( | 50 | − | 48 | ) |
| 63 | t | − | 4473 | − | 50 | t | + | 50 | × | 71 | = | 170 | − | t | × | 50 | + | t | × | 48 |
| 63 | t | − | 4473 | − | 50 | t | + | 3550 | = | 170 | − | t | × | 50 | + | t | × | 48 |
| 13 | t | − | 923 | = | 170 | − | 2 | t |
| 13 | t | + | 2 | t | = | 170 | + | 923 |
| 15 | t | = | 170 | + | 923 |
| 15 | t | = | 1093 |
| t | = | 1093 | ÷ | 15 |
| = | 1093 | × | 1 15 |
| t | = | 1093 15 |
| t | = | 72.866667 |