| ( | x | − | 3 | ) | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) | = | 800 |
| 方程左边 = | x | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) | − | 3 | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) |
| = | x | × | 500 | − | x | × | 10 | × | 5 | − | x | × | 4 | ÷ | 1 10 | − | 3 | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) |
| = | x | × | 500 | − | x | × | 50 | − | x | × | 40 | − | 3 | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) |
| = | 410 | x | − | 3 | ( | 500 | − | 10 | × | 5 | − | 4 | ÷ | 1 10 | ) |
| = | 410 | x | − | 3 | × | 500 | + | 3 | × | 10 | × | 5 | + | 3 | × | 4 | ÷ | 1 10 |
| = | 410 | x | − | 1500 | + | 150 | + | 120 |
| = | 410 | x | − | 1230 |
| 410 | x | − | 1230 | = | 800 |
| 410 | x | = | 800 | + | 1230 |
| 410 | x | = | 2030 |
| x | = | 2030 | ÷ | 410 |
| = | 2030 | × | 1 410 |
| = | 203 | × | 1 41 |
| x | = | 203 41 |
| x | = | 4.95122 |