| ( | 4 | + | x | − | 3 | ) | ( | 500 | − | 1 10 | x | ) | = | 800 |
| 方程左边 = | 4 | ( | 500 | − | 1 10 | x | ) | + | x | ( | 500 | − | 1 10 | x | ) | − | 3 | ( | 500 | − | 1 10 | x | ) |
| = | 4 | × | 500 | − | 4 | × | 1 10 | x | + | x | ( | 500 | − | 1 10 | x | ) | − | 3 | ( | 500 | − | 1 10 | x | ) |
| = | 2000 | − | 2 5 | x | + | x | ( | 500 | − | 1 10 | x | ) | − | 3 | ( | 500 | − | 1 10 | x | ) |
| = | 2000 | − | 2 5 | x | + | x | × | 500 | − | x | × | 1 10 | x | − | 3 | ( | 500 | − | 1 10 | x | ) |
| = | 2000 | + | 2498 5 | x | − | x | × | 1 10 | x | − | 3 | ( | 500 | − | 1 10 | x | ) |
| = | 2000 | + | 2498 5 | x | − | x | × | 1 10 | x | − | 3 | × | 500 | + | 3 | × | 1 10 | x |
| = | 2000 | + | 2498 5 | x | − | x | × | 1 10 | x | − | 1500 | + | 3 10 | x |
| = | 500 | + | 4999 10 | x | − | x | × | 1 10 | x |
| 500 | + | 4999 10 | x | − | x | × | 1 10 | x | = | 800 |