| X | − | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | − | ( | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | ÷ | 2 | + | 800 | ) | − | 480 | = | 0 |
| 方程左边 = | X | − | 1 | ÷ | 2 | × | X | + | 600 | − | ( | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | ÷ | 2 | + | 800 | ) | − | 480 |
| = | X | − | 1 2 | X | + | 600 | − | ( | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | ÷ | 2 | + | 800 | ) | − | 480 |
| = | 1 2 | X | + | 120 | − | ( | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | ÷ | 2 | + | 800 | ) |
| = | 1 2 | X | + | 120 | − | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | ÷ | 2 | − | 800 |
| = | 1 2 | X | − | 680 | − | ( | 1 | ÷ | 2 | × | X | − | 600 | ) | × | 1 2 |
| = | 1 2 | X | − | 680 | − | 1 | ÷ | 2 | × | X | × | 1 2 | + | 600 | × | 1 2 |
| = | 1 2 | X | − | 680 | − | 1 4 | X | + | 300 |
| = | 1 4 | X | − | 380 |
1 4 | X | − | 380 | = | 0 |
1 4 | X | = | 0 | + | 380 |
1 4 | X | = | 380 |
| X | = | 380 | ÷ | 1 4 |
| = | 380 | × | 4 |
| X | = | 1520 |