| 90 | + | ( | x | − | 180 | ) | × | 3 5 | + | ( | 460 | − | x | ) | × | 1 2 | = | 507 2 |
| 方程左边 = | 90 | + | x | × | 3 5 | − | 180 | × | 3 5 | + | ( | 460 | − | x | ) | × | 1 2 |
| = | 90 | + | x | × | 3 5 | − | 108 | + | ( | 460 | − | x | ) | × | 1 2 |
| = | - | 18 | + | 3 5 | x | + | ( | 460 | − | x | ) | × | 1 2 |
| = | - | 18 | + | 3 5 | x | + | 460 | × | 1 2 | − | x | × | 1 2 |
| = | - | 18 | + | 3 5 | x | + | 230 | − | x | × | 1 2 |
| = | 212 | + | 1 10 | x |
| 212 | + | 1 10 | x | = | 507 2 |
1 10 | x | = | 507 2 | − | 212 |
1 10 | x | = | 83 2 |
| x | = | 83 2 | ÷ | 1 10 |
| = | 83 2 | × | 10 |
| = | 83 | × | 5 |
| x | = | 415 |