| ( | 500 | − | 480 | ) | ÷ | ( | 540 | − | 480 | ) | = | ( | x | − | 670 | ) | ÷ | ( | 760 | − | 697 | ) |
| 方程两边同时乘以: | ( | 540 | − | 480 | ) | , | ( | 760 | − | 697 | ) |
| ( | 500 | − | 480 | ) | ( | 760 | − | 697 | ) | = | ( | x | − | 670 | ) | ( | 540 | − | 480 | ) |
| 500 | ( | 760 | − | 697 | ) | − | 480 | ( | 760 | − | 697 | ) | = | ( | x | − | 670 | ) | ( | 540 | − | 480 | ) |
| 500 | ( | 760 | − | 697 | ) | − | 480 | ( | 760 | − | 697 | ) | = | x | ( | 540 | − | 480 | ) | − | 670 | ( | 540 | − | 480 | ) |
| 500 | × | 760 | − | 500 | × | 697 | − | 480 | ( | 760 | − | 697 | ) | = | x | ( | 540 | − | 480 | ) | − | 670 | ( | 540 | − | 480 | ) |
| 500 | × | 760 | − | 500 | × | 697 | − | 480 | ( | 760 | − | 697 | ) | = | x | × | 540 | − | x | × | 480 | − | 670 | ( | 540 | − | 480 | ) |
| 380000 | − | 348500 | − | 480 | ( | 760 | − | 697 | ) | = | x | × | 540 | − | x | × | 480 | − | 670 | ( | 540 | − | 480 | ) |
| 31500 | − | 480 | ( | 760 | − | 697 | ) | = | 60 | x | − | 670 | ( | 540 | − | 480 | ) |
| 31500 | − | 480 | × | 760 | + | 480 | × | 697 | = | 60 | x | − | 670 | ( | 540 | − | 480 | ) |
| 31500 | − | 480 | × | 760 | + | 480 | × | 697 | = | 60 | x | − | 670 | × | 540 | + | 670 | × | 480 |
| 31500 | − | 364800 | + | 334560 | = | 60 | x | − | 361800 | + | 321600 |
| 1260 | = | 60 | x | − | 40200 |
| - | 60 | x | = | - | 40200 | − | 1260 |
| - | 60 | x | = | - | 41460 |
| 41460 | = | 60 | x |
| 60 | x | = | 41460 |
| x | = | 41460 | ÷ | 60 |
| = | 41460 | × | 1 60 |
| = | 691 | × | 1 |
| x | = | 691 |