7 10 | x | × | 51 | ÷ | 56 | + | ( | 20 | − | x | ) | × | 64 | ÷ | 80 | × | 34 | ÷ | 64 | = | 24 | × | 17 | ÷ | 40 |
| 方程左边 = | 51 80 | x | + | ( | 20 | − | x | ) | × | 17 40 |
51 80 | x | + | ( | 20 | − | x | ) | × | 17 40 | = | 24 | × | 17 | ÷ | 40 |
| 方程左边 = | 51 80 | x | + | 20 | × | 17 40 | − | x | × | 17 40 |
| = | 51 80 | x | + | 17 2 | − | x | × | 17 40 |
| = | 17 80 | x | + | 17 2 |
17 80 | x | + | 17 2 | = | 24 | × | 17 | ÷ | 40 |
| 方程右边 = | 51 5 |
17 80 | x | + | 17 2 | = | 51 5 |
17 80 | x | = | 51 5 | − | 17 2 |
17 80 | x | = | 17 10 |
| x | = | 17 10 | ÷ | 17 80 |
| = | 17 10 | × | 80 17 |
| = | 1 | × | 8 |
| x | = | 8 |