| ( | 7113 | − | X | ) | ÷ | 8 | = | X | + | 450 |
| 方程左边 = | 7113 | × | 1 8 | − | X | × | 1 8 |
| = | 7113 8 | − | X | × | 1 8 |
7113 8 | − | 1 8 | X | = | X | + | 450 |
| - | 1 8 | X | − | X | = | 450 | − | 7113 8 |
| - | 9 8 | X | = | 450 | − | 7113 8 |
| - | 9 8 | X | = | - | 3513 8 |
3513 8 | = | 9 8 | X |
9 8 | X | = | 3513 8 |
| X | = | 3513 8 | ÷ | 9 8 |
| = | 3513 8 | × | 8 9 |
| = | 1171 | × | 1 3 |
| X | = | 1171 3 |
| X | = | 390.333333 |