| ( | 2 5 | − | 1 20 | ) | x | + | ( | 290 | − | 2 5 | x | ) | ÷ | 3 10 | × | ( | 3 10 | − | 1 20 | ) | = | 250 |
| 方程左边 = | 2 5 | x | − | 1 20 | x | + | ( | 290 | − | 2 5 | x | ) | × | 10 3 | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | ( | 290 | − | 2 5 | x | ) | × | 10 3 | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 290 | × | 10 3 | ( | 3 10 | − | 1 20 | ) | − | 2 5 | x | × | 10 3 | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 2900 3 | ( | 3 10 | − | 1 20 | ) | − | 4 3 | x | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 2900 3 | × | 3 10 | − | 2900 3 | × | 1 20 | − | 4 3 | x | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 290 | − | 145 3 | − | 4 3 | x | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 725 3 | − | 4 3 | x | ( | 3 10 | − | 1 20 | ) |
| = | 7 20 | x | + | 725 3 | − | 4 3 | x | × | 3 10 | + | 4 3 | x | × | 1 20 |
| = | 7 20 | x | + | 725 3 | − | 2 5 | x | + | 1 15 | x |
| = | 1 60 | x | + | 725 3 |
1 60 | x | + | 725 3 | = | 250 |
1 60 | x | = | 250 | − | 725 3 |
1 60 | x | = | 25 3 |
| x | = | 25 3 | ÷ | 1 60 |
| = | 25 3 | × | 60 |
| = | 25 | × | 20 |
| x | = | 500 |