| 30888 | = | ( | ( | 220 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 8 | × | 81 |
| 方程右边 = | ( | ( | 220 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 648 |
| 30888 | = | ( | ( | 220 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 648 |
| 方程右边 = | ( | 220 | + | 260 | ) | × | 63 | × | 17 20 | − | x | × | 17 20 | + | 648 |
| = | ( | 220 | + | 260 | ) | × | 1071 20 | − | x | × | 17 20 | + | 648 |
| = | 220 | × | 1071 20 | + | 260 | × | 1071 20 | − | 17 20 | x | + | 648 |
| = | 11781 | + | 13923 | − | 17 20 | x | + | 648 |
| = | 26352 | − | 17 20 | x |
| 30888 | = | 26352 | − | 17 20 | x |
17 20 | x | = | 26352 | − | 30888 |
17 20 | x | = | - | 4536 |
| x | = | - | 4536 | ÷ | 17 20 |
| = | - | 4536 | × | 20 17 |
| x | = | - | 90720 17 |
| x | = | - 5336.470588 |