| ( | 2000 | − | 1000 | ) | ÷ | ( | 3000 | − | 1500 | ) | = | ( | B | − | 383 10 | ) | ÷ | ( | 519 5 | − | B | ) |
| 方程两边同时乘以: | ( | 3000 | − | 1500 | ) | , | ( | 519 5 | − | B | ) |
| ( | 2000 | − | 1000 | ) | ( | 519 5 | − | B | ) | = | ( | B | − | 383 10 | ) | ( | 3000 | − | 1500 | ) |
| 2000 | ( | 519 5 | − | B | ) | − | 1000 | ( | 519 5 | − | B | ) | = | ( | B | − | 383 10 | ) | ( | 3000 | − | 1500 | ) |
| 2000 | ( | 519 5 | − | B | ) | − | 1000 | ( | 519 5 | − | B | ) | = | B | ( | 3000 | − | 1500 | ) | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 2000 | × | 519 5 | − | 2000 | B | − | 1000 | ( | 519 5 | − | B | ) | = | B | ( | 3000 | − | 1500 | ) | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 2000 | × | 519 5 | − | 2000 | B | − | 1000 | ( | 519 5 | − | B | ) | = | B | × | 3000 | − | B | × | 1500 | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 207600 | − | 2000 | B | − | 1000 | ( | 519 5 | − | B | ) | = | B | × | 3000 | − | B | × | 1500 | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 207600 | − | 2000 | B | − | 1000 | ( | 519 5 | − | B | ) | = | 1500 | B | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 207600 | − | 2000 | B | − | 1000 | × | 519 5 | + | 1000 | B | = | 1500 | B | − | 383 10 | ( | 3000 | − | 1500 | ) |
| 207600 | − | 2000 | B | − | 1000 | × | 519 5 | + | 1000 | B | = | 1500 | B | − | 383 10 | × | 3000 | + | 383 10 | × | 1500 |
| 207600 | − | 2000 | B | − | 103800 | + | 1000 | B | = | 1500 | B | − | 114900 | + | 57450 |
| 103800 | − | 1000 | B | = | 1500 | B | − | 57450 |
| - | 1000 | B | − | 1500 | B | = | - | 57450 | − | 103800 |
| - | 2500 | B | = | - | 57450 | − | 103800 |
| - | 2500 | B | = | - | 161250 |
| 161250 | = | 2500 | B |
| 2500 | B | = | 161250 |
| B | = | 161250 | ÷ | 2500 |
| = | 161250 | × | 1 2500 |
| = | 129 | × | 1 2 |
| B | = | 129 2 |
| B | = | 64.5 |