| X | + | 500 | + | ( | X | + | 500 | ) | ÷ | 15 4 | = | 600 |
| 方程左边 = | X | + | 500 | + | X | × | 4 15 | + | 500 | × | 4 15 |
| = | X | + | 500 | + | X | × | 4 15 | + | 400 3 |
| = | 19 15 | X | + | 1900 3 |
19 15 | X | + | 1900 3 | = | 600 |
19 15 | X | = | 600 | − | 1900 3 |
19 15 | X | = | - | 100 3 |
| X | = | - | 100 3 | ÷ | 19 15 |
| = | - | 100 3 | × | 15 19 |
| = | - | 100 | × | 5 19 |
| X | = | - | 500 19 |
| X | = | - 26.315789 |