| ( | x | − | 4 | ) | ÷ | ( | - | 5 | ) | = | ( | 3 | x | − | 4 | ) | ÷ | 15 |
| 方程两边同时乘以: | ( | - | 5 | ) |
| ( | x | − | 4 | ) | = | ( | 3 | x | − | 4 | ) | ÷ | 15 | × | ( | - | 5 | ) |
| x | − | 4 | = | ( | 3 | x | − | 4 | ) | ÷ | 15 | × | ( | - | 5 | ) |
| x | − | 4 | = | 3 | x | ÷ | 15 | × | ( | - | 5 | ) | − | 4 | ÷ | 15 | × | ( | - | 5 | ) |
| x | − | 4 | = | 1 5 | x | ( | - | 5 | ) | − | 4 15 | ( | - | 5 | ) |
| x | − | 4 | = | - | 1 5 | x | × | 5 | − | 4 15 | ( | - | 5 | ) |
| x | − | 4 | = | - | 1 | x | − | 4 15 | ( | - | 5 | ) |
| x | − | 4 | = | - | 1 | x | + | 4 15 | × | 5 |
| x | − | 4 | = | - | 1 | x | + | 4 3 |
| x | + | 1 | x | = | 4 3 | + | 4 |
| 2 | x | = | 4 3 | + | 4 |
| 2 | x | = | 16 3 |
| x | = | 16 3 | ÷ | 2 |
| = | 16 3 | × | 1 2 |
| = | 8 3 | × | 1 |
| x | = | 8 3 |
| x | = | 2.666667 |