| ( | 66 | − | 58 | ) | ÷ | ( | 58 | − | 49 | ) | = | ( | 85 | − | T | ) | ÷ | ( | T | − | 71 | ) |
| 方程两边同时乘以: | ( | 58 | − | 49 | ) | , | ( | T | − | 71 | ) |
| ( | 66 | − | 58 | ) | ( | T | − | 71 | ) | = | ( | 85 | − | T | ) | ( | 58 | − | 49 | ) |
| 66 | ( | T | − | 71 | ) | − | 58 | ( | T | − | 71 | ) | = | ( | 85 | − | T | ) | ( | 58 | − | 49 | ) |
| 66 | ( | T | − | 71 | ) | − | 58 | ( | T | − | 71 | ) | = | 85 | ( | 58 | − | 49 | ) | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 66 | × | 71 | − | 58 | ( | T | − | 71 | ) | = | 85 | ( | 58 | − | 49 | ) | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 66 | × | 71 | − | 58 | ( | T | − | 71 | ) | = | 85 | × | 58 | − | 85 | × | 49 | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 4686 | − | 58 | ( | T | − | 71 | ) | = | 4930 | − | 4165 | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 4686 | − | 58 | ( | T | − | 71 | ) | = | 765 | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 4686 | − | 58 | T | + | 58 | × | 71 | = | 765 | − | T | ( | 58 | − | 49 | ) |
| 66 | T | − | 4686 | − | 58 | T | + | 58 | × | 71 | = | 765 | − | T | × | 58 | + | T | × | 49 |
| 66 | T | − | 4686 | − | 58 | T | + | 4118 | = | 765 | − | T | × | 58 | + | T | × | 49 |
| 8 | T | − | 568 | = | 765 | − | 9 | T |
| 8 | T | + | 9 | T | = | 765 | + | 568 |
| 17 | T | = | 765 | + | 568 |
| 17 | T | = | 1333 |
| T | = | 1333 | ÷ | 17 |
| = | 1333 | × | 1 17 |
| T | = | 1333 17 |
| T | = | 78.411765 |