| 10 | ( | 5 | x | + | 40 | ) | ÷ | 4 | + | 13 | x | = | 2650 |
| 方程左边 = | 5 2 | ( | 5 | x | + | 40 | ) | + | 13 | x |
5 2 | ( | 5 | x | + | 40 | ) | + | 13 | x | = | 2650 |
| 方程左边 = | 5 2 | × | 5 | x | + | 5 2 | × | 40 | + | 13 | x |
| = | 25 2 | x | + | 100 | + | 13 | x |
| = | 51 2 | x | + | 100 |
51 2 | x | + | 100 | = | 2650 |
51 2 | x | = | 2650 | − | 100 |
51 2 | x | = | 2550 |
| x | = | 2550 | ÷ | 51 2 |
| = | 2550 | × | 2 51 |
| = | 50 | × | 2 |
| x | = | 100 |