| ( | 8520 | + | 35 | + | X | ) | × | 7 200 | = | 4 | X |
| 方程左边 = | 8520 | × | 7 200 | + | 35 | × | 7 200 | + | X | × | 7 200 |
| = | 1491 5 | + | 49 40 | + | X | × | 7 200 |
| = | 11977 40 | + | 7 200 | X |
11977 40 | + | 7 200 | X | = | 4 | X |
7 200 | X | − | 4 | X | = | - | 11977 40 |
| - | 793 200 | X | = | - | 11977 40 |
11977 40 | = | 793 200 | X |
793 200 | X | = | 11977 40 |
| X | = | 11977 40 | ÷ | 793 200 |
| = | 11977 40 | × | 200 793 |
| = | 11977 | × | 5 793 |
| X | = | 59885 793 |
| X | = | 75.517024 |