4 5 | x | + | 10 | × | 13 5 | + | ( | x | − | 10 | ) | × | 7 2 | = | 641 10 |
| 方程左边 = | 4 5 | x | + | 26 | + | ( | x | − | 10 | ) | × | 7 2 |
4 5 | x | + | 26 | + | ( | x | − | 10 | ) | × | 7 2 | = | 641 10 |
| 方程左边 = | 4 5 | x | + | 26 | + | x | × | 7 2 | − | 10 | × | 7 2 |
| = | 4 5 | x | + | 26 | + | x | × | 7 2 | − | 35 |
| = | 43 10 | x | − | 9 |
43 10 | x | − | 9 | = | 641 10 |
43 10 | x | = | 641 10 | + | 9 |
43 10 | x | = | 731 10 |
| x | = | 731 10 | ÷ | 43 10 |
| = | 731 10 | × | 10 43 |
| = | 17 | × | 1 |
| x | = | 17 |