| ( | ( | 220 | + | 220 | ) | × | 21 | − | x | ) | × | 9 10 | + | 8 | × | 21 | = | 6636 |
| 方程左边 = | ( | ( | 220 | + | 220 | ) | × | 21 | − | x | ) | × | 9 10 | + | 168 |
| ( | ( | 220 | + | 220 | ) | × | 21 | − | x | ) | × | 9 10 | + | 168 | = | 6636 |
| 方程左边 = | ( | 220 | + | 220 | ) | × | 21 | × | 9 10 | − | x | × | 9 10 | + | 168 |
| = | ( | 220 | + | 220 | ) | × | 189 10 | − | x | × | 9 10 | + | 168 |
| = | 220 | × | 189 10 | + | 220 | × | 189 10 | − | 9 10 | x | + | 168 |
| = | 4158 | + | 4158 | − | 9 10 | x | + | 168 |
| = | 8484 | − | 9 10 | x |
| 8484 | − | 9 10 | x | = | 6636 |
| - | 9 10 | x | = | 6636 | − | 8484 |
| - | 9 10 | x | = | - | 1848 |
| 1848 | = | 9 10 | x |
9 10 | x | = | 1848 |
| x | = | 1848 | ÷ | 9 10 |
| = | 1848 | × | 10 9 |
| = | 616 | × | 10 3 |
| x | = | 6160 3 |
| x | = | 2053.333333 |