| ( | 7 | x | − | 650 | ) | ÷ | ( | 5 | x | + | 650 | ) | = | 3 | ÷ | 4 |
| 方程两边同时乘以: | ( | 5 | x | + | 650 | ) |
| ( | 7 | x | − | 650 | ) | = | 3 | ÷ | 4 | × | ( | 5 | x | + | 650 | ) |
| 7 | x | − | 650 | = | 3 | ÷ | 4 | × | ( | 5 | x | + | 650 | ) |
| 7 | x | − | 650 | = | 3 | ÷ | 4 | × | 5 | x | + | 3 | ÷ | 4 | × | 650 |
| 7 | x | − | 650 | = | 15 4 | x | + | 975 2 |
| 7 | x | − | 15 4 | x | = | 975 2 | + | 650 |
13 4 | x | = | 975 2 | + | 650 |
13 4 | x | = | 2275 2 |
| x | = | 2275 2 | ÷ | 13 4 |
| = | 2275 2 | × | 4 13 |
| = | 175 | × | 2 |
| x | = | 350 |